M E M O I R S 
OF 
T 11 E A M E RI CAN AC A DEM Y 
OF 
ARTS AND SCIENCES 
Yol. XII. —No. V. 
CAMBRIDGE: 
.1 O H X WILSON AND SO N. 
fflmurrsito JJrrss. 
August, 1902. MASSACHUSETTS INSTITUTE OF TECHNOLOGY, 
Boston, 
Dear Sir:- 
In reply to your kind letter of Lay 5th asking 
for a copy of the paper by Lr. Winslow and myself upon 
Ice in tne Lemoirs ol t :e American Academy of Arts and 
Sciences, Vo . XII, ho. 5, I may say that one of these 
reprints was forwarded to the Surgeon General or the 
Surgeon General’s Office twj or three months ago when 
the reprints were distributed, and unless I am mistaken, 
an acknowledgement of its receipt reached me shortly 
afterwards. 
If, however, on investigation you find that you 
have no such copy and that I am mistaken, I shall be 
very glad to send one to the Surgeon General’s library,— 
the r■ nk and importance of which is very well known to 
us. 
With esteem, I am, dear Sir, 
Respectfully yours, 
f'r. Robert Fletcher, 
Surgeon General’s Office, 
7th and B Sts.,S.W., 
Washington, r. C. V. 
I. EXPERIMENTS ON THE EFFECT OF FREEZING AND OTHER LOW 
TEMPERATURES UPON THE VIABILITY OF THE BACILLUS OF 
TYPHOID FEVER, WITH CONSIDERATIONS REGARDING ICE AS 
A VEHICLE OF INFECTIOUS DISEASE. 
II. STATISTICAL STUDIES ON THE SEASONAL PREVALENCE OF 
TYPHOID FEVER IN VARIOUS COUNTRIES AND ITS RELATION 
TO SEASONAL TEMPERATURE. 
BY 
WILLIAM T. SEDGWICK, Ph.D., and CHARLES-EDWARD A. WINSLOW, S. M., 
Professor of Biology, Instructor in Biology, 
In the Massachusetts Institute of Technology, 
BOSTON, MASSACHUSETTS. 
WITH EIGHT PLATES. 
Presented March 12, 1902. 
(Preliminary Communication, December 13, 1809.) TABLE OF CONTENTS. 
PAGE 
I. INTRODUCTORY 471 
II. A REVIEW OF THE LITERATURE RELATING TO ICE AS A VEHICLE OF 
DISEASE AND TO THE BACTERIOLOGY OF ICE 472 
A. Infectious Diseases attributed to Polluted Ice and Ice-cream 472 
B. Bacteria in Natural Ice, Snow and Hail, and in Ice-cream 475 
C. Experiments on the Effect of Freezing and other Low Temperatures upon 
the Viability of Bacteria 478 
I). Quantitative Studies upon the Destruction of Bacteria by Freezing and other 
Low Temperatures 483 
III. EXPERIMENTS BY THE AUTHORS ON THE EFFECT OF COLD UPON THE 
BACILLI OF TYPHOID FEVER 487 
A. Experiments on the Percentage Reduction of Typhoid Fever Bacilli effected 
by Freezing for Different Periods of Time 487 
B. Experiments on the Effect of Alternate Freezing and Thawing upon the 
Bacilli of Typhoid Fever 499 
C. Experiments on the Effect of Temperatures slightly above the Freezing- 
Point upon Typhoid Bacilli in Water 501 
D. Experiments on the Viability of Typhoid Bacilli in Earth at Various Tem- 
peratures 508 
E. Experiments on the Effect of Sedimentation and Crystallization during the 
Freezing of Typhoid Fever Bacilli in Water 516 
IV. DEDUCTIONS FROM THE EXPERIMENTS CONCERNING ICE AS A VEHICLE 
OF INFECTIOUS DISEASE, WITH SPECIAL REFERENCE TO THE PROB- 
LEMS OF ICE-SUPPLY AND THE PUBLIC HEALTH 519 
PART I. 470 
CONTENTS. 
PAGE 
I. A REVIEW OF THE LITERATURE RELATING TO THE SEASONAL PREVA- 
LENCE OF TYPHOID FEVER 521 
II. STATISTICAL STUDIES BY THE AUTHORS ON SEASONAL VARIATIONS 
IN TEMPERATURE, AND IN THE PREVALENCE OF TYPHOID FEVER 
IN VARIOUS COUNTRIES 537 
III. INTERPRETATION OF THE STATISTICAL RESULTS 507 
IV. CONCLUSION OF THE AUTHORS THAT THE SEASONAL PREVALENCE OF 
TYPHOID FEVER DEPENDS MAINLY UPON SEASONAL TEMPERATURE 509 
PART II. 
PART III. 
BIBLIOGRAPHY 573 
A. On Disease attributed to Polluted Ice and Ice-cream 573 
B. On the Bacteriology of Natural Ice, Snow, and Hail, and of Ice-cream . . 573 
C. On the Effect of Freezing and other Low Temperatures upon Bacteria . . 574 
D. On Quantitative Studies of the Destruction of Bacteria by Freezing . . . 576 
E. On the Seasonal Prevalence of Typhoid Fever and its Relation to Seasonal 
Temperature 576 PART I. 
I. INTRODUCTORY. 
In view of the fact that the micro-organism which is commonly considered to be 
the cause of typhoid fever appears to be able to survive for longer or shorter periods 
in the environment of man, it becomes important to discover, as nearly as may be, 
its behavior under various natural conditions. Some knowledge of this kind we have 
already in the case of heat and light; some, also, in respect to low temperatures 
under certain conditions. But a careful review of the present state of our knowl- 
edge in regard to the influence of cold upon the bacillus of typhoid fever shows that 
much still remains to be done in order to make our knowledge in this direction 
more precise. 
The subject assumes great practical importance when we begin to consider the 
influence of external conditions upon the longevity of the bacillus in nature, par- 
ticularly in those regions in which there is a considerable variation of climate. It 
was a theory formerly widely held that the specific organism of typhoid fever was not 
only capable of enduring for a long time outside the human body, but even that a 
residence in earth, filth heaps, and the like was an essential phase in its life his- 
tory. Modern researches have thrown grave doubt upon this earlier theory, but at 
the same time rigid inquiry into epidemics and further knowledge of the disease itself 
have shown how readily the micro-organism may become widely distributed in the 
environment. Prolonged and careful studies of the influence of temperature upon 
the bacillus of typhoid fever, have led us to believe that this factor plays a part in 
the seasonal distribution of the disease which is of the highest importance, making it 
possible to explain, by the co-operation of this and other factors, such as light and 
dryness, certain phenomena hitherto inexplicable or little understood. An obvious 
and direct application of the principles worked out concerns one of the principal food 
supplies of man, and an important section of the following paper is therefore devoted 
fo a consideration of the danger of the conveyance of the disease in question by pol- 
luted ice. II. A REVIEW OF THE LITERATURE RELATING TO ICE AS A VE- 
HICLE OF DISEASE AND TO THE BACTERIOLOGY OF ICE. 
A. INFECTIOUS DISEASES ATTRIBUTED TO POLLUTED ICE AND ICE-CREAM. 
The interest of the authors in this subject was first aroused by the practical 
questions connected with ice supply and the public health. As will appear in the 
paragraphs immediately following, diseases, and particularly typhoid fever, have not 
infrequently been attributed to impure ice. 
The first outbreak of disease directly ascribed to this source was reported in this 
country in 1875,(1) at the summer resort of Rye Beach. Dr. Nichols of Boston, who 
was called in to investigate the affair, found the illness, a more or less severe 
intestinal disorder, confined to the guests of one of the two large hotels of the place. 
The other hotel and adjacent cottages were unaffected. The milk and water supplies 
and the drainage appeared above suspicion. The ice for the hotel, however, was cut 
on a small pond whose waters were rendered very foul by a mass of putrescent 
matter, composed of marsh mud and decomposing sawdust. A chemical analysis 
of the ice, and of the water from the pond, showed high total organic matter and 
high ammonia, both free and albuminoid. Three cases of the disease outside the hotel 
directly following the use of this ice made the evidence still stronger. Three years 
later Dr. Smart, U. S. A.,(2) attributed some cases of a “ malarial remittent fever ” 
in a Rocky Mountain army post to the contamination of mountain streams by melting 
snow. The high organic content of the water in early spring was probably due to 
this cause, and he believed that the “ mat erics morbV' of malaria had a similar 
origin. In the summer of 1879 an outbreak of dysentery occurred in Connecticut 
which is discussed in the Second Report of the Board of Health of that State.(3) Out 
of the eleven persons, including the family residing in a certain farmhouse, two hired 
men, and relatives who came to assist in nursing, there were eight cases of dysentery, 
three of them fatal, and two cases of persistent diarrhoea. The drinking water in use 
gave satisfactory results on anatysis, but the soil adjoining the house was damp and 
polluted, and the ice used came from a small stream which served as a running place 
for pigs. Analysis of the ice-water showed high ammonias, and this appeared to the SEDGWICK AND WINSLOW. BACILLUS OF TYPHOID FEVER. 
473 
investigators the most probable cause of the disease. In the Report of the same 
Board for 1882,(4) an interesting single case of typhoid fever is cited as probably 
derived from ice. The patient had lived alone for some months in a house whose 
sanitary conditions were apparently perfect. He was inordinately fond of ice-water, 
and the ice for his house was cut on a small pond near by. It appeared on investiga- 
tion that the drains from some laborers’ houses emptied directly into the pond, and 
that in these houses there had been three cases of typhoid fever during the previous 
summer. Attention was also called to the general danger from ice supply, by the 
Connecticut State Board of Health in 1880, by the Massachusetts State Board in 
1876 and 1889, by the Michigan Board in 1882 and 1884, by the New Hampshire 
Board in 1882, the New York Board in 1886, the Minnesota Board in 1886, and the 
sanitary authorities of Chicago in 1896 and of Milwaukee in 1876. 
Duclaux (0 appears to have been the first European to give the matter marked 
attention, .although a recent French writer(7) mentions an ice epidemic at “ Eveshem,” 
in 1882, of which we have found no other account. Duclaux enlarged at length upon 
the danger from ice, especially the artificial ice made in Paris from the water of 
certain highly polluted canals. In 1893 Professor Riche(6) made a long report to the 
Conscil d'hyqihie et de salubrite de la Seine upon the dangers to the inhabitants of 
Paris from the sale of highly polluted ice. He quoted a letter from Pasteur as 
follows: “ Le docteur Roux vous a dit son opinion, et c’est aussi la mienne, que toute 
eau impropre a la boisson l’est egalement pour preparer, en hiver, de la glace pour 
1’alimentation. Les microbes inoffensifs ou pathogenes resistent presque tons a des 
temperatures meme tres basses.” M. Riche showed that much of the Paris ice came 
from contaminated sources, and recommended strong legal restrictions upon its sale. 
Finally, Dr. Dorange, in the Revue d' described a supposed ice-epidemic 
of typhoid fever at the military post of Rennes in the autumn of 1895. Eight 
lieutenants of the regiment there stationed were taken ill between the twelfth and 
the twenty-fifth of December. The fact that these officers did not habitually live in 
common but had all been present at a regimental banquet upon the fourth of 
December, pointed to that occasion as the moment of infection. The higher officers 
dined in a separate room, and used no water but the town supply, which was excel- 
lent. The lieutenants, on the other hand, drank a “ tisane ” of champagne mixed with 
chilled water. The man who provided this claimed that it also was derived from the 
regular town-supply. The fact that the town water could be obtained by him only 
from a considerable distance and under strict police regulations, led Dr. Dorange to 
suspect that he had made use of the water in a reservoir which stood in the room 474 
SEDGWICK AND WINSLOW. BACILLUS OF TYPHOID FEVER. 
where he cooled his decanters and which received the meltings from his stock of 
ice. The ice supply of the town was considered highly polluted. The additional 
facts are cited that the menus of the different classes of officers were the same, and 
that certain of the petty officers who did not drink from the “ tisane ” but made 
use of beer instead, escaped the disease. 
Altogether it appears probable that the milder intestinal disorders, caused by 
mere decomposing organic matter and not by specific germs, have at times been 
caused by polluted ice. The Rye Beach epidemic was carefully and thoroughly 
studied, and leads directly to that conclusion. With respect to typhoid fever the case 
is different. The only ice-epidemic of typhoid fever which has come to our notice, 
viz., that at Rennes, rests on a doubtful chain of circumstances, and lacks the con- 
firmation of a complete exclusion of all possible factors other than ice. We have 
been unable, then, to find any conclusive evidence that typhoid fever has been caused 
by polluted ice-supply. 
A number of English epidemics of typhoid fever, more or less clearly traced to 
ice-cream, should be noticed here, although the conditions are quite different from 
those which obtain in the case of ice. The first of these epidemics occurred in the 
English sanitary districts of Greenwich and Rotherhithe in 1892.(8) During the last 
week of September and the two months next following 511 cases were reported, the 
beginning of the attack in 15 per cent of the cases falling on October 1 and in 57 per 
cent of the cases falling in the fortnight preceding October 3. A remarkably large 
piopoi tion of the victims were young children. The water supply and sewerage of 
the four separate foci of infection were different and apparently all in good condi- 
tion. The milk supply of the households attacked came from seven dairy farms, and 
in many cases consisted only of condensed milk. Suspicion was then directed to the 
ice-cream sold by Italians from barrows in the street. A careful canvass of one 
neighborhood in which 56 cases of typhoid fever had occurred showed that 924 
persons lived in houses where ices had not been eaten, 232 lived in houses where 
ices had been obtained from shops, and 395 in houses where ices had been obtained 
from a certain ice-cream vendor. All the cases of typhoid fever were in this latter 
class. A detailed examination of the cases in all the infected areas showed that 
88.9 per cent of the sufferers had eaten ices, and that, of these, 91.4 per cent had 
obtained their supply from ten Italian vendors living in a certain Mill Lane, of whom 
one was the dealer above mentioned. The sanitary conditions in Mill Lane were 
found to be abominable ; and in the family of one of the purveyors of ice-cream two 
children had sickened with typhoid fever on July 29 and August 5 respectively. SEDOWICK AND WINSLOW. BACILLUS OF TYPIIOII) FEVER; 
475 
An epidemic of typhoid fever which attacked over 800 persons in the county of 
Renfrew, in Scotland, in 1803, was attributed by Dr. A. C. Munro partly to ice-cream 
and partly to the public water-supply.(9) Out of the first 180 cases G3 were shown to 
have eaten ice-cream prepared by a dealer in whose family a case of typhoid fever 
had occurred during the previous month. The patient had been in intimate contact 
with the ice-cream business during the greater part of her illness. 
Vaughan and Perkins, in 1895,(10) ascribed two epidemics of severe, but not fatal, 
intestinal disease to a new pathogenic bacillus which they isolated from ice-cream in 
one case and from cheese in the other. The germ belonged to the colon group, and 
the authors note that neither twenty-nine days of continuous freezing nor alternate 
freezing and thawing could destroy its vitality. 
I)r. Hope, in 1898,(,1) studied an epidemic affecting 27 school children in Liverpool 
in which the only clue appeared to be the presence of all the patients at a fair just at 
the time of infection. Here 24 of the children had eaten ice-cream and two more 
had partaken of “chip” potatoes sold by an Italian in whose house there had been 
two cases of typhoid fever. 
In these cases of infection from ice-cream there is, of course, no certainty that the 
disease germs were actually frozen. The possibility of contamination from spoons, 
vessels, and the hands of the vendor might easily account for all the phenomena. 
Even if the infection was really carried in the ice-cream the exposure to a low 
temperature must have been a relatively short one. The same reasoning applies to 
the famous Plymouth, Pa., epidemic of typhoid fever. This little mining town had 
1200 cases of the disease and 130 deaths among its 8000 inhabitants in 1885, and the 
investigation(12) clearly traced the infection to the dejecta of a single typhoid fever 
patient which were thrown out on the snow on the banks of the brook supplying 
the town with water, and which had been washed in by the first general thaw of the 
spring. It may easily have been that the discharges thrown out during the day or 
two preceding the thaw were never really frozen at all. In any case the conditions 
affecting germs imbedded in a solid mass of rich food material are quite different 
from those which obtain in the formation of ice upon a stream or pond. 
B. BACTERIA IN NATURAL ICE, SNOW, AND HAIL, AND IN ICE-CREAM. 
In spite of the absence of epidemiological evidence, it has been the common 
opinion of sanitarians that ice might lie an important source of infection for typhoid 
fever or any other germ disease. Its apparent purity was shown by the earliest 
bacteriologists to be deceptive. Burdon-Sanderson,(13) in 1871, found that liquid 476 
SEDGWICK AND WINSLOW. BACILLUS OF TYPHOID FEVER. 
culture media showed bacterial growth when inoculated with melted ice or with 
snow. In the next year, Cohn (14) described experiments in which nutrient solutions 
containing bacteria were not sterilized by exposure to a temperature ranging as 
low as —18° C. for about 6 hours or by a temperature with a minimum of —7° C. for 
18 hours. 
Professor Joseph Leidy, in 1884,(15) exhibited, at a meeting of the Academy of 
Natural Sciences at Philadelphia, snow water derived from melted ice, containing 
not only Infusoria but also Rotifers and Worms. Pohl, in the same year,(16) recorded 
the finding of many bacteria in snow and ice, 110 per centimeter in Neva ice, and 
20,774 in one sample of bubbly ice. He also found bacteria in falling snow, the 
number decreasing with the continuation of the storm. A report on the ice supply 
of the city of Syracuse(17) was made to the New York Board of Health in 1886 in 
which the presence of a great number of bacteria was noted in ice from Onondaga 
Lake and the Erie Canal. In 1888 Breunig(18) found 1310-2760 germs in ice, and 
Kowalski09' analyzed sixty samples of natural ice, and found from 10 to 1000 germs 
per cubic centimeter, no sample being sterile. Still another paper was published at 
this period, 1888-89, by Heyroth,(20J who studied the Berlin ice-supply, and, in 25 
samples, found from 2 to 133,000 bacteria per cubic centimeter, the highest figures 
corresponding to chemical analyses which showed the most marked pollution. An 
elaborate report was made by the State Board of Health of Massachusetts in 1889,(21) 
in which 238 samples of natural ice from the ponds and streams of this State 
were analyzed bacteriologically. The figures for ice from different portions of the 
cake were as follows : — 
Number of 
Samples. 
Bacteria per c.c. 
Maximum. 
Minimum. 
Average. 
Transparent Ice 
27 
893 
0 
105 
Clear Ice 
75 
370 
0 
15 
Bubbly Ice 
113 
1950 
0 
111 
Snow Ice 
23 
2968 
0 
622 
A “Lancet” analytical sanitary commission made an examination of some ice sold 
in London in 1893, and found that while all the specimens gave good chemical analyses, 
two out of the six examined contained 400 to 700 bacteria per cubic centime ter.(22) 
Girard and Bordas,23) published some startling analyses of the Paris ice-supply also 
in 1893. They found a minimum of 23,000 colonies and a maximum of 100,000 
colonies per cubic centimeter, including the Bacillus coli communis and a patho- SEDGWICK AND WINSLOW. BACILLUS OF TYPHOID FEVER. 
477 
genic vibrio. These quantitative results are so large as to suggest that the sam- 
ples were probably not planted promptly after melting. 
Christomonas(24) has recently studied artificial ice, and reports that when water 
containing 71 bacteria per centimeter was frozen, 450 germs per centimeter were 
found in the central core and 8-10 in the clear ice at the sides. 
The bacteria of snow and hail have also received considerable attention. Soon 
after the work of Pohl,(I6) Janowsky<26) made analyses of old and of freshly fallen 
snow in the neighborhood of Kiew, and found bacteria in both, less in the former than 
in the latter. Schmelk(26) studied the bacterial life in the snow of a Norwegian 
glacier and in the chill streams flowing therefrom ; and in a later paper(27) he recorded 
small numbers in both snow and ice at Christiania. Bujwid(2K) found 21,000 bacteria 
per cubic centimeter in the analysis of a melted hail-stone; and Foutin(29) in Russia 
obtained similar, though smaller, figures. 
Giacosa(30) found bacteria present in small numbers in snow lying at an elevation 
of 3800 meters above the sea, and Abbott(31) noted 703 colonies per cubic centi- 
meter in hail. Dominguez,(32) in 1892, published a paper on the bacterial content of 
hail; and finally, Scofone,(33) who accompanied a scientific expedition to Monte 
Rosa in 1894-95, recorded the presence of small numbers of bacteria in melted 
snow obtained from high altitudes. In the following year he gave the results 
of some examinations made on a plateau 2460 meters above the sea, which confirmed 
his previous conclusion that the bacteria in the deeper layers of the snow were 
somewhat more numerous than in the superficial layers.(34) 
The number of bacteria present in ice-cream has been shown at times to be 
enormous. Klein(35) found the germ content of London ice-cream very high, and B. 
coli communis frequently present. Nield-Cook(3,) recorded from 5,000,000 to 
14,000,000 germs per cubic centimeter in ice-cream from the same source, the 
majority being colon bacilli. Stevenson(37) testified, at the trial of an Italian ice- 
cream vendor, that he had found over 4000 germs per cubic centimeter, of which 
three proved to be B. coli communis. Wilkinson(38) reached similar results, and 
quoted, without reference, the following results of other observers: — 
Macfadyen 119,000 — 7,000,000 bacteria per cubic centimeter. 
Kanthack 8,000,000 - 13,000,000 “ “ « “ 
Foulerton 500,000 - 7,000,000 « “ “ “ 
In this connection it may be interesting to note the very small numbers of 
bacteria present in the air and water of the Arctic regions. Nystrom (39) discovered 
this fact in 1868 by the exposure of a number of flasks of putrescible matter, after the 478 
SEDGWICK AND WINSLOW. BACILLUS OF TYPHOID FEVER. 
manner of Pasteur. Couteaud(4W) found but one colony in 19 flasks exposed to Arctic 
air, the experiment being carried on, however, on the open sea, so that the result is 
not surprising. He also found but few species present in some analyses of water and 
of soil. In the Nansen expedition the poverty of the bacterial flora of the air was 
noted. Finally, Dr. Levin(41) of Stockholm made an elaborate study of the subject 
with the Natthorst expedition. In 21,600 liters of air examined at twenty different 
places 3 germs alone were found, all in one sample. In sea water, at the sur- 
face, 11 germs per centimeter occurred, belonging apparently to two characteristic 
species. Fresh water and melted ice and snow gave similar small numbers. Samples 
from considerable depths in the ocean showed somewhat higher numbers than were 
obtained at the surface. Finally, tests of the alimentary canals of various Arctic 
animals and birds showed many of them to be completely sterile. 
C. EXPERIMENTS ON THE EFFECT OF FREEZING AND OTHER LOW 
TEMPERATURES UPON THE VIABILITY OF BACTERIA. 
Laboratory experiments have confirmed the conclusion, drawn from the examina- 
tion of natural ice, that freezing is by no means always fatal to germ life. Von 
Frisch(42) froze putrefying solutions and reduced the frozen mass to a temperature of 
—87* C., and after some hours found that sterilization had not ensued. 
Pictet »and Young(43) subjected bouillon cultures of several species to a tempera- 
ture below —70 C. for 108 hours, during twenty hours of which time the temperature 
was below —130°. After this treatment B. anthracis and the bacillus of “ charbon 
symptomatique ” were alive and virulent; B. subtilis and B. ulna grew readily; half 
the inoculations made from the cultures of two species of micrococci grew and half 
did not. Finkler and Prior(44) stated that the vibrio described by them could survive 
a temperature of —4* C. for many days. McKendrick,(45) in a communication to the 
British Association in 1885, noted that putrescible liquids were not sterilized by a 
temperature of C. Forster(4r,) found that the phosphorescent bacteria which he 
isolated from fish preserved by cold storage grew vigorously at 0° C. Fischer(47) 
isolated 5 species of bacteria from the water of the harbor at Kiel, and 9 other forms 
from the soil, all capable of multiplying at 0°. In the research already cited,(20) Hey- 
roth froze gelatine stick-cultures of various species for from seven to ten days, and 
then placed them once more under favorable conditions; out of 30 species, thus 
treated, 25 showed growth, though 5 of these had partially lost their liquefying power. 
D’Arsonval,(48) in 1891, recommended liquefied carbonic acid for use in steriliz- 
ing organic extracts, and stated that when the treatment is prolonged, especially SEDGWICK AND WINSLOW. BACILLUS OF TYPHOID FEVER. 
479 
if broken by a return to 40 for a time, “ nothing living can resist it,” but his own 
and other later researches showed the error of this conclusion. Forster, in 1892,(49) 
examined various natural waters, foods, wastes, sweepings, and soils for bacteria 
capable of growth at 0 , and found a few such forms in water, earth, and street 
sweepings. When present at all they occurred in great numbers. Forster also 
demonstrated the multiplication of bacteria and the progress of decomposition in 
butcher’s meat chopped up and kept in an ice calorimeter. Fischer(50) noted that 
Miller’s vibrio and the vibrio of Finkler and Prior could withstand a freezing tempera- 
ture for some days. 
Pictet, in 1893,<51) studied the effect of cold on plants and animals of the most 
widely separated classes. Of the bacteria he subjected 30 to 35 species to tempera- 
tures ranging as low as —200 C. by immersing them in liquid air, but the viability of 
the germs used appeared unaffected after “ prolonged ” treatment of this sort. 
D’Arsonval and Charrin(52) subjected cultures of Bacillus pyocyaneus to a temperature 
of —40 to —60 C. with the result that, in six out of eight instances, the germs 
remained alive. 
In another paper(63) these authors mentioned that Bacillus pyocyaneus after 
exposure to —40 , -60, and —95 C. exhibited profound changes in morphology and 
physiology. For some generations the descendants of the frozen germs showed 
elongated, ovoid, and other abnormal forms, and their colonies on gelatine were also 
of unusual character. Weber(54) noted that Hofer’s bacillus, producing a contagious 
disease among Crustacea, can endure a temperature of —40 C. for four hours, as well 
as repeated thawings and freezings. 
Professor Mason(56) recorded the exposure of cultures of “ordinary bacteria” to the 
temperature of solid carbon dioxide for many hours without causing their destruction. 
Still more recently Ravenel(6C) submitted cultures of the anthrax, diphtheria, and 
typhoid bacilli, and of Bacillus prodigiosus to the temperature of liquid air, 191 below 
zero Centigrade, for periods of three hours, thirty minutes, one hour, and one hour 
respectively ; in no case could any weakening of the vegetative power of the culture 
be detected. 
Besides Pictet and Young(43) and Ravenel(5C) a number of other observers have 
tested the effect of low temperatures upon specific pathogenes. Cadeac and Malet(67) 
found that tuberculous matter kept frozen for four months still produced charac- 
teristic symptoms in guinea pigs. In some work on the spores and vegetative forms 
of Bacillus anthracis carried out by one of the Franklands and Dr. Templeman,(68) it 
was found that a single freezing at —20 C. reduced the numbers present in water from 480 
SEDGWICK AND WINSLOW. BACILLUS OF TYPHOID FEVER. 
15,000 to 3500 per cubic centimeter, and after 29 successive freezings, extending 
over a period of three months, 3000 germs per centimeter could still develop. Evi- 
dently the vegetative forms were killed by one freezing, and the spores, not at all. 
Another culture which was spore-free showed reduction from 8000 germs per centimeter 
to 2 per centimeter after one freezing, sterilization following the second freezing. 
Gabritschewsky, Wladimiroff, and Kressling and Gladin quoted by Kasansky(59) 
found that the plague germ could bear an artificial cold of —22° C. for two hours and 
natural cold ranging from 0° to —20° C. for from twelve to forty days. Kasansky 
himself in 1897-98 made some interesting experiments on the resistance of the specific 
organisms of plague and diphtheria against cold. The cultures were placed outside the 
window of the laboratory at Kasan, sheltered from light but exposed to the winter’s 
cold, which ranged from a maximum of 5° C. to —34 C. Bouillon cultures of the 
plague germ showed life after thirty-two days ; four months’ exposure sterilized most 
of the tubes, but in one case growth was obtained after six months. Of the agar 
cultures tested some died in four months, and others contained living germs after 
five months and a half. Sixteen bouillon tubes of the diphtheria bacillus were kept 
for six months under similar conditions, and one tube only showed growth at the end 
of that time ; two of the others, however, still gave positive results on the fifty-third 
and one hundred and eighteenth day, respectively. 
Abel(60) exposed cultures of the diphtheria germ on blood serum and on dried 
threads to the winter’s cold at Greifswald, and compared them with cultures kept 
in the room in the same condition. The first race used persisted on the blood serum 
for the whole period of eighty-six days both in the room and out of doors, although 
in the second case the growth obtained was meagre after the fiftieth day. The dried 
germs had disappeared by the sixty-eighth day out of doors and by the seventy- 
fourth indoors. Of the second race the serum culture remained alive in the room 
all through the experiment; the frozen one showed no growth after the seventy- 
fourth day. The threads gave living germs up to the seventy-fourth day in-doors and 
up to the fifty-sixth day out-doors. The thread** of the third race gave precisely the 
same result; the serum cultures kept in the room gave vigorous growths up to 
the end of the experiment, while only two colonies developed from the inoculation 
of the frozen tube. The out-door temperature during the experiment varied from 
12° C. to -20° C. 
With regard to the behavior of the typhoid bacillus in ice, there is more evidence 
available. Dr. Carl Seitz(G1) noted in 1886 that cultures of this organism in gelatine, 
bouillon, and milk were not rendered sterile by the continuance of a temperature SEDGWICK AND WINSLOW. — BACILLUS OF TYPHOID FEVER. 
481 
below 3 C., .although the growth on gelatine at the low temperature was very much 
retarded. Dr. Hillings, in this country,(62) described a single experiment in which five 
cubic centimeters of sterile water were inoculated with the typhoid germ and frozen 
by the out-door cold. On the next day the frozen mass was thawed, and three gelatine 
tubes and one agar tube were inoculated with portions of it. Three of the four tubes 
showed typical growths. Chantemesse and Widal(63 recorded the freezing of bouillon 
cultures of the same microbe without sterilization. Bash enow(C4) stated that typhoid 
germs survived exposure for thirteen days to a temperature between —8’ and —15 C. 
Janowsky published in 1890 some very extended researches(66) in which he used pure 
cultures of the typhoid bacillus in bouillon and froze them by means of ice and salt, 
ice and chloride of calcium or carbon dioxide and ether. He made no quantitative 
estimations ; but bouillon frozen by each of the above methods could still produce 
growth in Esmarch roll-tubes. Janowsky tried also the effect of successive freezings, 
using1 the calcium-chloride mixture. After the culture had solidified, it was left in 
o 
the freezing mixture for fifteen minutes, then thawed in a water bath at 25°—30 C., a 
sample taken, and the cycle repeated. This was done three times a day ; and during 
the night the culture was kept at 2°—5° C. After twelve such freezings sterilization 
had not been accomplished; the development of the frozen bacilli was, however, much 
retarded. To imitate more closely the conditions in nature, Janowsky placed a 
bouillon culture and two flasks in which were threads bearing the germ in a dried 
condition, in a wire cage out of doors. Four sets of experiments were conducted, in 
three of which periods of seven, ten, and twelve days, respectively, did not suffice for 
sterilization. In the fourth set of cultures the bouillon tube showed no growth after 
nineteen days; the minimum temperature during the period had been—17 C. and 
the maximum 4 , the culture thawing and freezing three times. Finally, among ex- 
periments on the typhoid bacillus must be mentioned a remarkable paper by Rem- 
linger,(6C) in which he states that he used a culture of B. typhi of such virulence 
that .5 c.c. would kill a guinea pig in 3G-48 hours. He took agar cultures of this 
germ out of the incubator every two or three hours to immerse them in water, cooled 
down to 22°—23°, for ten minutes. After ten days of this treatment the cultures had 
entirely lost their virulence, and after thirty-five days their power of growth as well. 
The author does not state whether control experiments were made or not. 
Even more extensive is the literature with respect to the effect of cold on the 
cholera vibrio. Koch, the discoverer of the organism, stated that it was not destroyed 
by a temperature of-10° C. in ten hours.(C7) Raptschewski(68) found that cholera germs 
could endure for a month severe cold, ranging as low as -15° C., but that a tempera- 482 
SEDGWICK AND WINSLOW. BACILLUS OF TYPHOID FEVER. 
ture of 21 C. was fatal. Von Babes *fl9) succeeded in keeping a series of agar cultures 
of the vibrio alive, though exposed to the cold of a Berlin winter (1884-85) ranging 
as low as —14° C. In the year 1893 no less than eight papers were published dealing 
with the relation of the cholera germ to cold. Schruff(70) found that a broth culture 
made from fresh choleraic faeces was not sterilized by eight months’ exposure to the 
winter’s cold ranging as low as—12.5° C. Finkelnburg(71) noted that cultures of an old 
laboratory race were killed out in ten days, while cultures of fresher races were not. 
Karschinski(72) stated that a cholera culture with which he worked was sterilized in 
four days by an average cold of —12.7° C. with a minimum of —17.6° C. Renk(73) froze 
the germs in sterilized river water at —5° C. to —7° C. and kept the flasks at that tem- 
perature, removing one each day for examination. Growth resulting from the melted 
ice was tested by cover-glass examination and by the Indol reaction. After five 
days’ uninterrupted freezing the cholera germs disappeared, but when the period was 
broken by the melting of the contents of a flask for analysis and its re-freezing, a little 
longer period was necessary. When unsterilized river water was inoculated and frozen, 
the bacteria present fell off from 1,483,000 per centimeter to 62,445 in twenty-four 
hours, and to 4480 after three days. The cholera germs in this case could not be de- 
tected after seventy-two hours, and in one case not after thirty-nine hours. Uffelmann (74) 
found that cholera germs died out in five days at—15.5° C. and in three days at —24.8° C. 
Wnukow,(75) on the other hand, stated that gelatine stick cultures of the same micro- 
organism were subjected for forty days to an outdoor temperature between —lc C. and 
—32° C. without sterilization. Double thawing and freezing also failed to destroy their 
power of growth. Montefusco(76) tested the pathogenicity of chilled cholera cultures for 
guinea pigs, and recorded that a temperature of —10° to —15° C. entirely destroyed their 
virulence in half an hour, while a temperature between 0° and -5° only weakened it. 
Cultivation at 37.5° soon restored the powers of the germs, but in the chilled and 
attenuated condition they produced a state of immunity in the animals injected. 
Abel(77) also mentions experiments in which cholera vibrios frozen in bouillon died out 
completely in from three to eight days. Kasansky,(78) in 1894, found that cholera 
cultures withstood for four months the winter’s cold at Kasan, where the temperature 
fell to — 31.8 C. One culture gave growth after twenty days of freezing. Some 
were thawed and refrozen as many as twelve times. After longer exposure, for five 
months, the cultures gave no growth. Kasansky demonstrated nearly as great a 
resistance to cold in the case of the vibrios of Finkler-Prior, Miller, Deneke, and 
MetschnikofF. Finally, some light was thrown on the discordant results of previous 
observers by the work of Weiss,(79) who inoculated tubes of broth and water from SEDGWICK AND WINSLOW. — BACILLUS OF TYPHOID FEVER. 
483 
the Spree with cholera cultures and froze them, thawing, sampling, and refreezing 
the tubes daily. In broth the germs persisted for twenty-one days, but in river 
water only for five days, the addition of a little broth to the water prolonging 
the time to eight days. Fresh intestinal contents of a cholera patient showed no 
vibrios after two or three freezings.1 
From this long series of experiments it is evident that sterilization of rich 
cultures of bacteria cannot always be secured by the action of even very extreme 
cold. Hence the conclusion was drawn that the freezing of water could not be 
trusted at all to remove its bacterial impurities. There are, however, two objections 
to this line of reasoning. In the first place, the effect of cold on germs suspended 
in water may differ materially from its action on similar organisms when in a richly 
nutrient medium. In the second place, even if sterilization does not result from freez- 
ing in cultures containing millions of bacteria, it is conceivable that such a large 
proportion of the microbes may perish as to render very slender the chance of danger 
from ice formed under natural conditions. Experiments have shown that easily 
detected germs like B. prodigiosus can pass through a sand filter when applied to 
the surface in large numbers under certain conditions; yet a sand filter, in prac- 
tice, is regarded as an efficient protection. A quantitative determination of the per- 
centage reduction actually effected by freezing is required before drawing conclusions 
as to the sanitary significance of ice-supply in relation to the public health. 
I). QUANTITATIVE STUDIES UPON THE DESTRUCTION OF BACTERIA BY 
FREEZING AND OTHER LOW TEMPERATURES. 
The quantitative studies of Frankland (58) on B. anthracis, of Renk (73) on river- 
water bacteria, and of Christomonas,(24) on artificial ice, have already been mentioned. 
Work on the disappearance of bacteria in the freezing of natural water had, however, 
been undertaken at a much earlier period. Pengra,(80) in 1884, made an actual 
microscopic count of the organisms present, working with bacteria (species not stated), 
and other micro-organisms from decomposing meat juice, infusion of hay, and stag- 
nant pools. His freezing was done by the winter’s cold, and his figures were 
obtained by counting the contents of ten drops and taking an average. He found 
1 Macfadyen (Lancet, I, 1900, p. 849) has recently exposed cultures of Bacillus typhi, Bacillus coli commu- 
nis, Bacillus diphtheria!, Spirillum choleric asiaticae, Bacillus proteus vulgaris, Bacillus acidi lactici, Bacillus anthra- 
cis (spore hearing), Staphylococcus pyogenes aureus, Bacillus phosphorescens, and Photobacterium balticum in solid 
and liquid cultures to the temperature of liquid air (-182° C. to -190° C.), for twenty hours without sterilization 
and without impairing the properties of the organisms in any degree. 
Macfadyen and Rowland (Lancet, Vol. I, 1900, p. 1130) treated the same organisms in broth emulsions in fine 
quill tubes with liquid air for seven days with the same results, except that a slightly delayed growth was noticed 
in some instances. 484 
SEDGWICK AND WINSLOW. BACILLUS OF TYPHOID FEVER. 
in the upper part of the ice 16 bacteria; in the lower part, only partially frozen, 
250 ; in the upper and lower parts of a duplicate unfrozen vessel of water, ICO and 
170, respectively. He obtained similar results with three of Infusoria, and 
concluded that 90 per cent of the organisms were removed by freezing. His experi- 
ments appear, however, to show crystallization effects principally. The first careful 
work on this subject was done by Fraenkel in Berlin.(81) He collected river water, and 
after planting samples, froze them artificially at —8 to —12° C., thawing after different 
periods. In two days 83 per cent of the water bacteria present were killed ; in three 
days 99 per cent; in five days, 90 per cent; in six days, 80 per cent; in six days, 
in another case, 93 per cent; and in nine days, 99 per cent. The different samples 
evidently varied greatly. Fraenkel also analyzed the regular Berlin ice-supply, and 
got results ranging from 21 to 9700 bacteria per cubic centimeter. He concluded 
that the ice was highly polluted and should not be taken into the system. About 
the same time Wolff huegel and Riedel(82) gave an account of some experiments in 
which flasks of tap-water were kept in the ice-chest without freezing, and showed 
the following reductions: after one day, from 148 germs per cubic centimeter to 126 
and from 150 to 115; after two days, from 123 to 69 and from 158 to 101 ; after 
three days, from 123 to 29 and from 156 to 33. 
In 1887 Dr. Prudden of New York published the most exhaustive review hitherto 
attempted of the subject of quantitative reduction, and the first in which specific 
pathogenic germs were used.(83) His tubes, in the experiments with the latter organisms, 
were inoculated from pure cultures and frozen at —10° to —1 C., and his results were 
as follows, the numbers in each case referring to bacteria per cubic centimeter : — 
B. prodigiosus. In water, 6300; in ice after 4 days, 2970 ; after 37 days, 22; 
after 51 days, 0. 
Proteus vulgaris. In water, 8320 ; in ice after 18 days, 88 ; 51 days, 0. 
Staphylococcus pyogenes aureus. In water, innumerable ; in ice after 18 days, 
224,598; 20 days, 46,486; 54 days, 34,320; 66 days, 49,280. 
Species unnamed. In water, innumerable ; in ice after 4 days, 571,450 ; 11 
days, 520,520; 51 days, 183,040; 65 days, 10,978; 77 days, 85,008. 
Species unnamed. In water, 800,000; in ice after 7 days, 0. 
B. typhi. In water, innumerable; in ice after 11 days, 1,019,403; 27 days, 
336,457; 42 days, 89,796; 69 days, 24,276; 77 days, 72,930; 103 days, 7348. 
Same. In water, 378,000; in ice after 12 hours, 164,780; after 3 days, 236,676; 
5 days, 21,416; 8 days, 76,032. 
Dr. Prudden then made certain experiments to determine the effect of alternate SEDGWICK AND WINSLOW. BACILLUS OF TYPHOID FEVER. 
485 
freezing and thawing, and obtained the following results- The tubes were here im- 
mersed in ice and salt at —20 C. 
B. TYPHI. 
In water . . . 40,89(5 
Frozen 24 hours 29,780 Refrozen 3 times 90 
“ 3 days 1,800 “ 5 “ 0 
“ 4 “ 950 “ 6 “ 0 
“ 5 “ 2,490 “ 6 “ 0 
B. PRODIGIOSUS. 
In water . . . 339,516 
Frozen 24 hours 36,410 llefrozen once 2,570 
“ 30 “ 41,580 “ 2 times 275 
“ 48 “ 14,440 “ 3 “ 15 
“ 96 “ 4,850 “ 4 “ 0 
STAPHYLOCOCCUS PYOGENES AUREUS. 
In water . . . 111,782 
Frozen 15 minutes 52,500 
“ 2 hours 21,300 
“ 24 “ 22,690 Refrozen once 13,495 
“ 48 “ 6,460 “ 3 times 110 
“ 96 “ 6,155 “ 4 “ 0 
Dr. Prudden found that, with fresh, active agar cultures of this stapli37lococcus 
49,280 germs remained alive, out of innumerable germs originally present, after 
sixty days; when cultures from old and dried agar were used, 162,000 germs dis- 
appeared entirely after five days. He ultimately drew the following conclusions from 
these experiments with pathogenic germs: 1. Many bacteria are killed by freez- 
ing. 2. The vitality of the original culture affects the number so killed. 3. The 
number killed varies with the species. 4. The number killed increases as the time 
of freezing is prolonged. 5. The resistance to cold varies with the individual bac- 
terium. G. Alternate freezing and thawing is very generally fatal. 
Dr. Prudden also froze natural waters with their native bacteria for varying periods, 
and obtained somewhat similar results. lie analyzed 270 samples of New York 
ice, and found an average of 2033 bacteria per cubic centimeter. The numbers 
were highest in the upper layers of snow ice and bubbly ice, and in ice cut in 
the immediate vicinity of Albany, falling off rapidly in ice five or six miles down the 
river. He concluded that this highly polluted ice probably contained the germs 
of typhoid fever and should not be taken into the human body. 486 
SEDGWICK AND WINSLOW. BACILLUS OF TYPHOID FEVER. 
Later in the same year Bordoni-Uffreduzzi(84) published a paper in which he took 
issue with Prudden on several points. He contended that the changes of temperature 
in the latter’s experiments were too abrupt, that the resistance of the germs worked 
with had been weakened by cultivation on artificial media, and that the effect had 
been abnormally severe on account of the small size of the tubes frozen. He himself 
analyzed the natural water in one of the municipal basins of Berlin, just before a 
frost, and then kept a large lump of the ice in a double-walled zinc chest, break- 
ing off samples for analysis every month. He found that about 90 per cent of 
the bacteria were killed, and thought the duration of the freezing did not make 
any material difference. His results, of course, varied very widely on account of 
the unequal distribution of the bacteria in the ice. 
Russell(85) a little later made similar experiments at Madison, Wisconsin, in which 
he found that the ice formed on Lake Mendota contained about 40 per cent of 
the germs present in the water itself. A report already cited(21) was made by 
the State Board of Health of Massachusetts in 1889 in which ice from fifty-eight 
sources was analyzed in comparison with the water on which it had formed. 
Averaging all results, there were 81 per cent as many bacteria present in the snow 
ice as in the water, 10 per cent in all the rest of the ice, and only 2 per cent 
in the clear ice. In the report of the Board for the next year,(86) Mr. Hiram F. Mills 
noted an isolated but significant experiment in which sterilized tap water was 
inoculated with the typhoid germ, kept in a bottle surrounded by ice and sampled 
at intervals. The results were as follows: — 
Day 
Number of Typhoid 
Bacilli. 
Day 
Number of Typhoid 
Bacilli. 
1 . . . 
.... 6120 
15 . . . 
.... 100 
5 . . . 
.... 3100 
20 . . . 
17 
10 . . . 
.... 490 
25 . . . 
.... 0 
Taken altogether, more exact studies confirm the rough estimate of Pengra 
that some 90 per cent of ordinary water bacteria are eliminated by the process 
of freezing. As to the percentage reduction of specific pathogenes and, in partic- 
ular, of the typhoid bacillus, probably the only form of great practical importance, 
the evidence is very meagre. The only results hitherto, as far as we have been 
able to discover, which fix quantitatively the effect of cold on this organism, are the 
three experiments of Dr. Prudden and the single experiment of the biologists of 
the Massachusetts State Board of Health. These certainly appear to form a slender 
basis for conclusions relative to the importance of ice-supply as a possible source 
of typhoid fever. SEDGWICK AND WINSLOW. — BACILLUS OF TYPHOID FEVEK. 
487 
111. EXPERIMENTS I1Y THE AUTHORS ON THE EFFECT OF COLD 
UPON THE BACILLI OF TYPHOID FEVER. 
A. EXPERIMENTS ON THE PERCENTAGE REDUCTION OF TYPHOID FEVER 
BACILLI EFFECTED BY FREEZING FOR DIFFERENT PERIODS OF TIME. 
Methods Employed. 
The following investigation was undertaken in order to so extend and amplify 
the work of Prudden as to obtain some idea of the average fatality occurring among 
typhoid bacilli in ice, and of the special conditions which affect such fatality. Pure 
cultures alone were used, as it is obvious that figures, to be of much value, must be 
determined separately for each specific germ. Great pains were taken to preserve, 
as far as possible, the vigor of the culture used, and new cultures from recent 
post-mortem examinations were obtained at intervals during the work. Finally, a 
large number of determinations were made for each set of conditions, in order to 
obtain average results free from the errors which may beset any individual case. 
Our experiments on the percentage reduction effected by freezing were carried 
on by freezing small tubes of infected water, as only in this way can the con- 
ditions of the experiment be rigidly controlled. Ordinary test-tubes, containing about 
10 cubic centimeters of sterilized tap water, were inoculated from a two or three 
day bouillon culture, and duplicate samples were at once planted. The ten tubes 
of the set under experiment were then placed in a double-walled tin vessel in 
which they were to be frozen. The inner vessel was a cylinder about 8 inches 
deep, nearly fdled with a mixture of equal parts of glycerine and 95 per cent 
alcohol; in this solution the tubes were immersed, being supported by a disc per- 
forated with holes to receive them. The solution served to make the lowering of 
temperature equal and gradual, and also acted as an antiseptic when the tubes broke, 
which sometimes happened when they contained too much water, or when the 
temperature went down too rapidly. In the outer vessel, which was jacketed with 
felt, was placed cracked ice which reduced the temperature of the glycerine-alcohol 
mixture to about 10—15 C. in from an hour to an hour and a half. The ice 
was then replaced by a mixture of ice and salt which completed the freezing 488 
SEDGWICK AND WINSLOW. — BACILLUS OF TYPIIOID FEVER. 
in a half or three-quarters of an hour more. The time occupied by the whole 
process of freezing is recorded in the tabulation of each experiment. The tem- 
perature, in the first set of experiments with “ Race A,” was observed by means 
of three mercury thermometers inserted in different parts of the liquid, and at the 
time when the tubes froze the thermometers registered 6 —7 below zero, C. In 
later experiments the temperature was observed by means of a minimum regis- 
tering spirit thermometer fastened to the inside of the cover of the inner cylinder, 
which recorded the temperature of the air just above the liquid in which the tubes 
were immersed. Partly on this account and probably partly because of its greater 
quickness of response, this thermometer gave lower records than did the mercury 
instruments in the first experiments. The readings of the spirit thermometer are 
given in the tables for each set of tubes. 
As soon as the tubes froze, they were removed from the freezer and either thawed 
at once or kept frozen in an ice-chest for a few hours, or placed in a cold-storage ware- 
house where they were kept for the longer periods at a temperature one or two 
degrees below zero, C. After the frozen condition had been maintained for the de- 
sired length of time, the contents of the tubes were thawed, shaken up, and sampled, 
again in duplicate. As a rule the samples taken from the thawed tubes were planted 
directly, while those made before freezing were diluted, one to ten, with sterilized 
water. All plates, for these quantitative determinations, were planted with common 
nutrient agar-agar, containing 1.25 per cent agar, 1.00 per cent Witte’s peptone, and 
.25 per cent salt, and having an acidity equal to 1.50 per cent. As the counts to be 
made were chiefly comparative, agar was preferred to any other medium, on account 
of its freedom from liquefaction. The plates were allowed to develop at the room 
temperature except in certain special cases to be noted later. Those made from the 
unfrozen water showed their maximum growth in three days and were counted after 
that interval. Those made from the thawed ice, however, were found to develop 
more slowly ; for them five days was generally found sufficient, although after the 
longer periods of freezing as much as ten days was sometimes allowed. The plates 
were finally counted with the aid of a hand lens. 
In many of the sets of experiments a control tube was included, which was treated 
just like the others except that it was not inoculated. Each series of tubes includes 
two lots of eight or ten each, frozen on two different days. 
The cultures were grown in bouillon (containing 1.00 per cent peptone, .25 per 
cent salt, and 1.00 per cent acid), and were changed twice or three times a week. In 
the earlier experiments the tubes were inoculated from a culture grown at the room SEDGWICK AND WINSLOW. BACILLUS OF TYPHOID FEVER. 
489 
temperature, itself inoculated from one grown at 37.5 C. In the later work the cul- 
tures were all kept at the room temperature. 
When experiments made on the culture obtained in November, 1898, gave results 
somewhat different from those given by the culture used in February, it was decided 
that still a third culture from a different source must be compared with the first two. 
The results showed that the descendants of these different stocks exhibited slight 
though constant and persistent differences in their reaction to cold. We have called 
the cultures derived from these original sources “ Races,” for physiological races 
they apparently must be considered. 
The first culture used, Race A, was obtained from the Boston City Hospital as a 
forty-hour-old blood-serum culture on February 23, 1898. Unfortunately, the history 
and tests applied to this culture in the Hospital were not recorded, beyond the fact 
that it had been isolated from an autopsy about two weeks previously, by the usual 
differential methods. 
Race B was obtained by the kindness of Dr. M. W. Richardson of the Massachu- 
setts General Hospital in the middle of November, 1898, with the following history. 
It had been isolated from the spinal canal, in a case of typhoid meningitis. It gave 
typical reactions in media as follows: bouillon, very motile; litmus milk, no coagulurn, 
slight acid production; sugar-agar, no gas; peptone solution, no indol ; gelatine slant 
stab, typical growth, no liquefaction ; arsenic bouillon (Thoinot), no growth ; Capaldi- 
Proskauer sol. No. 1, no growth ; potato, no visible growth ; tube medium of His, 
clouding without gas production ; typhoid serum, perfect reaction. 
Race C was obtained, January 14, 1899, by the courtesy of Dr. Pratt of the Boston 
City Hospital. It had been isolated, December 30, from the peritoneal cavity in a 
case of peritonitis following typhoid fever. It gave typical growths on the ordinary 
media, gelatine, bouillon, and glycerin-agar; it was motile in the hanging drop; it 
gave no indol and no gas in glucose solution ; it was decolorized by the Gram method 
and reacted to typhoid serum. 
Race D was isolated in the laboratory of the City Hospital, March 26, 1899, 
from the urethra. It was identified by the same tests used for Race C. 
Results Obtained. 
The percentage reductions recorded in the subjoined tables (pp. 492-498), sum- 
marized in final form, are as follows: — 490 
SEDGWICK AND WINSLOW. BACILLUS OF TYPHOID FEVER. 
PERCENTAGE REDUCTION OBSERVED IN EXPERIMENTS ON THE VIABILITY OF 
TYPHOID BACILLI IN ICE. 
Race A. 
B. 
c. 
D. 
Frozen 15 minutes 
59.4 
13.8 
U 
30 
u 
63.7 
u 
11 hours 
32.2 
(6 
2 
« 
73.6 
U 
3 
U 
41.4 
99.5 
74.8 
u 
6 
(( 
77.8 
97.0 
u 
12 
u 
38.6 
84.4 
a 
15 
u 
98.0 
u 
24 
u 
53.8 
82.7 
99.0 
u 
3 
days 
98.4 
99.9 
u 
7 
(( 
93.3 
99.5 
u 
2 
weeks 
99.8 
99.4 
99.9 
u 
4 
(( 
99.8 
u 
8 
u 
99.8 
u 
12 
u 
99.8 
Conclusions, 
1. Evidently we may reaffirm for the bacillus of typhoid fever the first of Prudden’s 
conclusions as to the various pathogenes with which he worked, namely, that many 
bacteria are killed by freezing. After two weeks’ exposure to the freezing tempera- 
ture an average of considerably over 99 per cent of the germs perished. Of the 140 
tubes inoculated with Races A, B, and C, and frozen for periods of two weeks and over, 
all but nine showed a reduction of over 99 per cent; and of the nine, all but one 
showed a reduction of 98 per cent or over. We may safely conclude that less than 1 
per cent of the typhoid germs present in water can survive fourteen days of freezing. 
2. During the first half-hour of freezing a heavy reduction takes place, amount- 
ing, perhaps, to 50 per cent. The tubes exposed for such short times to the un- 
favorable conditions exhibit a remarkable variability among themselves. In the 
same set one tube may show no reduction, while its neighbor is rendered almost 
sterile. Whether these differences are due to the varying physical conditions in 
the individual tubes, or to variations in the biological character of the loopful of 
bacteria used for inoculation, is uncertain. From the general harmony of the 
results obtained it appears that this factor of variability, whatever it may be, is 
practically eliminated by the averaging of 20 tubes. 
After this brief period of sudden but uncertain reduction, the destruction of the 
germs proceeds pretty regularly as a function of the time. Although the different 
races vary, there is in each race a steadily increased reduction, with slight variations, 
as the time of freezing is prolonged. After 14 days, even with the most resistant SEDGWICK ANI) WINSLOW. BACILLUS OF TYPHOID FEVER. 
491 
stock, Race B, the reduction was over 99 per cent. The reduction now proceeds, 
however, with increasing slowness ; the two or three germs per thousand which have 
survived thus far appear to possess special powers of resistance. Even after 12 weeks 
few of the individual tubes were rendered sterile. These results appeared so remark- 
able that special experiments were conducted to test their accuracy, as it was felt 
that perhaps the few germs developing from the thawed ice might have been intro- 
duced from the air, as was obviously the case in some instances. Fifty tubes of 
Races B and C were therefore frozen for periods of a week and a month ; plates 
were planted from them, with special precautions, and incubated at 37.5°; and 
the developing colonies were examined individually. The results, as the appended 
tables show (see p. 492), confirm those of the general investigation. Of the 20 tubes 
inoculated with Race B and frozen for a month, 10 were sterile; 9 gave one sterile 
plate, and one with one or two colonies of what proved to be extraneous germs; tube 
IV. alone gave, on one plate, 7 germs per cubic centimeter, which examination in 
the hanging drop, and growth on gelatine, and potato, in milk and glucose solu- 
tion, showed to be the original typhoid culture. So of the 30 tubes of Race C 
frozen for a week, 17 were sterile ; 9 showed contamination, one or two germs 
per plate; the other four showed 15, 4, 1, and 2G7 typhoid bacilli per cubic cen- 
timeter. These experiments confirm the results of those observers who froze 
typhoid cultures containing millions of germs without effecting sterilization. 
3. Prudden's statement that the number of bacteria killed by freezing varies 
with the species may be extended. It is evident that within the species B. typhi 
abdominal is there are races, each having a power of resistance of its own, depen- 
dent upon its history within and without the body. A comparison of the tables 
for the shorter periods of freezing shows clearly that Race C succumbed with much 
greater readiness to the influence of cold than did Race B ; while Races A and 
I) occupied an intermediate position. These differences appear constant through the 
various sets, so that in each race the progressively increased reduction with more 
prolonged freezing follows a parallel course. The facts cannot, we think, be at- 
tributed to differences in the immediate environment of the germs; such differ- 
ences do produce their effect, cultivation for a time on agar, for example, causing 
a decrease in resistance. The last sort of change is, however, temporary and may 
be quickly reversed by cultivation in bouillon ; while the race differences were 
permanent during the period of experimentation. Correlated with them were cer- 
tain minor characters ; for instance, the weakest race, Race C, grew more slowly 
than either of the others, and took perceptibly longer to produce a definite 
clouding in a liquid medium. 492 
SEDGWICK AND WINSLOW. — BACILLUS OF TYPHOID FEVER. 
Number 
of Tube. 
Average Number Bacteria per c.c. 
Reduction 
per cent. 
Unfrozen Water. 
Thawed Ice. 
1 
8750 
21 
99.8 
2 
910 
4 
99.5 
3 
4910 
1 
99.9+ 
4 
1465 
1 
99.9 
5 
900 
- 
— 
6 
2475 
4 
99.8 
7 
1260 
3 
99.8 
8 
1360 
10 
99.2 
9 
1535 
1 
99.9+ 
10 
1030 
7 
99.3 
11 
35210 
0 
100.0 
12 
22575 
3 
99.9+ 
13 
53060 
1 
99.9+ 
14 
8575 
— 
— 
15 
94580 
- 
— 
10 
116235 
1 
99.9+ 
17 
140175 
- 
— 
18 
95725 
4 
99.9+ 
19 
4602 
3 
99.9 
20 
229950 
2 
99.9+ 
Average . . 
99.8 
Race A. 
Series I. 
Number 
of Tube. 
Average Number Bacteria per c.c. 
Reduction 
per cent. 
Unfrozen Water. 
Thawed Ice. 
21 
10655 
17 
99.8 
22 
7695 
42 
99.4 
23 
3170 
2 
99.9 
24 
4265 
2 
99.9 
25 
90825 
1 
99.9+ 
26 
79625 
2 
99.9+ 
27 
5920 
6 
99.9 
28 
275 
1 
99.6 
29 
5400 
1 
99.9+ 
30 
2085 
3 
99.9 
31 
11480 
2 
99.9+ 
32 
24637 
12 
99.9 
33 
214200 
9 
99.9+ 
34 
2760 
7 
99.7 
35 
10430 
113 
98.9 
36 
32110 
4 
99.9+ 
37 
12757 
7 
99.9 
38 
26547 
4 
99.9+ 
39 
15155 
8 
99.9 
40 
19890 
1 
99.9+ 
Average . 
99.8 
Race A. 
Series II. 
Tubes 1-10, frozen March 2, 1898, in 1£ hours; thawed 
May 25, after 12 weeks. 
Tubes 11-20, frozen March 4, 1898,in 2 hours; thawed 
May 27, after 12 weeks. 
Tubes 21-30, frozen March 7,1808, in hours ; thawed 
May 2, after 8 weeks. 
Tubes 31-40, frozen March 12,1898, in 2\ hours; thawed 
May 7, after 8 weeks. 
Race A. 
Series III. 
Race A. 
Series IY. 
Number 
of Tube. 
Average Number Bacteria per c.c. 
Reduction 
per cent. 
Unfrozen Water. 
Thawed Ice. 
41 
3730 
6 
99.8 
42 
7880 
5 
99.9 
43 
2810 
6 
99.8 
44 
710 
7 
99.0 
45 
4470 
4 
99.9 
46 
9626 
3 
99.9+ 
47 
10482 
2 
99.9+ 
48 
3035 
12 
99.6 
49 
2085 
11 
99.5 
50 
5710 
5 
99.9 
61 
136710 
5 
99.9+ 
62 
41230 
3 
99.9+ 
63 
82215 
1 
99.9+ 
64 
26285 
5 
99.9 
65 
22225 
1 
99.9+ 
66 
19145 
3 
99.9+ 
67 
Control 
Control 
— 
68 
12320 
2 
99.9+ 
69 
10850 
4 
99.9+ 
70 
10920 
3 
99.9+ 
Average . . . 
99.8 
Number of 
Average Number Bacteria per c.c. 
Reduction 
Tube. 
Unfrozen Water. 
Thawed Ice. 
per cent. 
51 
24640 
25 
99.9 
52 
49000 
10 
99.9+ 
53 
48930 
30 
99.9 
54 
40450 
60 
99.8 
55 
29340 
30 
99.9 
56 
282240 
65 
99.9+ 
57 
44380 
110 
99.7 
58 
132300 
50 
99.9+ 
59 
24185 
25 
99.9 
60 
93555 
75 
99.9 
71 
55650 
- 
— 
72 
Control 
Control 
— 
73 
52395 
35 
99.9 
74 
9230 
70 
99.2 
75 
86870 
60 
99.9 
76 
46025 
25 
99.9 
77 
1740 
25 
98.6 
78 
41825 
5 
99.9+ 
79 
33155 
35 
99.9 
80 
23250 
30 
99.9 
Average . . . 
99.8 
Tubes 41-50, frozen March 16,1898, in 2 hours ; thawed 
April 13, after weeks. 
Tubes 61-70, frozen March 19,1898, in hours; thawed 
April 16, after loeeks. 
Tubes 51-60, frozen March 18,1898, in 1J hours ; thawed 
April 1, after 2 tveeks. 
Tubes 71-80, frozen March 21,1898, in hours ; thawed 
April 4, after 2 weeks. SEDGWICK AND WINSLOW. BACILLUS OF TYPHOID FEVER. 
493 
Race A. 
Series V 
Race A. 
Series VI. 
Number 
of Tube. 
Average Nuuilier it*-term per c c 
Reduction 
per cent. 
Unfrozen Water. 
Thawed Ice. 
171 
028425 
48090 
92.3 
172 
5365 
2040 
01.9 
173 
520380 
8010 
98.3 
171 
355950 
122535 
05.0 
175 
354090 
3(5540 
89.7 
170 
200010 
19775 
90.4 
177 
474390 
4000 
99.0 
17H 
402020 
— 
— 
MM 
3305 
15 
99.5 
192 
3300 
40 
98.8 
19.1 
103320 
30 
99.9+ 
191 
133875 
275 
99.8 
195 
348055 
315315 
9.6 
196 
40 
70 
0.0 
197 
214200 
350 
99.8 
198 
1(59155 
(545 75 
(51.8 
Averntje . 
77.8 
Number of 
Tube. 
Average Number Bacteria per c.c. 
Reduction 
per cent. 
Unfrozen Water. 
Thawed Ice. 
151 
40775 
21980 
4(5.1 
152 
39235 
17080 
5(5.5 
153 
454(55 
14770 
07.5 
154 
2(5530 
15190 
42.7 
155 
3(5295 
14385 
00.4 
156 
10710 
5110 
52.3 
157 
23520 
3800 
83.8 
158 
1272(50 
40005 
08.0 
181 
300 
15 
95.0 
182 
51030 
90(50 
81.1 
183 
132(55 
1410 
89.4 
181 
20475 
2955 
85.0 
185 
14595 
1145 
92.2 
186 
23415 
805 
9(5.0 
187 
223(55 
2915 
87.0 
188 
22(50 
— 
— 
Average . . 
73.0 
Tubes 171-178, frozen May 0, 1808, in 2 hours ; thawed 
same day, after 6‘ hours. 
Tubes 191-198, frozen May 13,1898, in hours ; thawed 
same day, after 6' hours. 
Tubes 151-158, frozen April 30, 1808, in 2\ hours; 
thawed, same day, after 2 hours. 
Tubes 181-188, frozen May 11, 1808, in 2$ hours; 
thawed same day, after 2 hours. 
Race A. 
Series VII. 
Race A. 
Series YTTT. 
NumlH*r 
of Tube. 
Average Number Bacteria per c.c. 
Reduction 
per cent. 
Unfrozen Water. 
Thawed Ice. 
HI 
1820 
990 
45.9 
82 
2795 
40 
98.6 
83 
1205 
25 
98.1 
81 
820 
0 
100.0 
85 
355 
15 
95.8 
86 
430 
15 
90.5 
87 
2515 
2075 
17.5 
88 
1285 
0 
100.0 
89 
755 
10 
98.7 
90 
165 
5 
97.0 
101 
25970 
11340 
50.3 
102 
11005 
8015 
31.3 
10.1 
16965 
4555 
73.1 
101 
30730 
26355 
14.2 
105 
Control 
Control 
— 
100 
8750 
6510 
25.6 
107 
9205 
5525 
. 40.0 
108 
9345 
3380 
63.8 
109 
20090 
11410 
43.2 
110 
14315 
9170 
35.9 
Average . 
Number 
Average Number Bacteria i>cr c.c. 
Ked uction 
of Tube. 
Unfrozen Water. 
Thawed Ice 
per cent. 
121 
500220 
715 
99.9 
122 
492345 
252640 
48.7 
123 
57420 
27755 
51.7 
124 
53795 
705 
98.7 
125 
Control 
Control 
— 
120 
5705 
955 
83.2 
127 
124110 
7175 
94.2 
128 
77490 
9800 
87.3 
101 
33810 
17640 
47.9 
102 
270900 
275940 
.3 
103 
349020 
120960 
65.3 
101 
246645 
111930 
54.6 
105 
120775 
62050 
48.6 
100 
472500 
236880 
49.9 
107 
756550 
505575 
33.2 
108 
170100 
123795 
27.2 
Average . 
59.4 
Tubes 121-128, frozen April 23, 1898, in 1J hours; 
thawed same day, after 15 minutes. 
Tubes 161-168, frozen May 4, 1898, in 1£ hours ; 
thawed same day, after 15 minutes. 
Tubes 81 90, frozen March 25,1898, in 1J hours ; thawed 
same day, after SO minutes. 
Tubes 101-110, frozen April 9, 1898, in 2 hours 
thawed same day, after- SO minutes. 494 
SEDGWICK AND WINSLOW. — BACILLUS OF TYPHOID FEVER. 
Race B. 
Series I. 
Race B. 
Series II. 
Number 
of Tube. 
Average Number Bacteria per c.c. 
Reduction 
per cent. 
Unfrozen Water. 
Thawed Ice. 
71 
37275 
462 
98.8 
72 
45990 
27 
99.9 
73 
41685 
189 
99.5 
74 
63210 
382 
99.4 
75 
26250 
773 
97.1 
70 
34230 
599 
98.3 
77 
18800 
378 
98.0 
78 
40110 
467 
98.8 
79 
42525 
613 
98.6 
80 
50295 
47 
99.9 
81 
144325 
23 
99.9+ 
82 
108360 
11 
99.9+ 
83 
123165 
8 
99.9+ 
84 
89775 
7 
99.9+ 
85 
83790 
9 
99.9+ 
80 
58275 
10 
99.9+ 
87 
104895 
21 
99.9+ 
88 
83475 
11 
99.9+ 
89 
187110 
51 
99.9+ 
90 
56595 
15 
99.9+ 
Average . . . 
99.4 
Number 
of Tube. 
Average Number Bacteria per c.c. 
Reduction 
per cent. 
Unfrozen Water. 
Thawed Ice. 
Ill 
52605 
3622 
93.1 
112 
88200 
1386 
98.4 
113 
95235 
4018 
95.8 
114 
63065 
1270 
98.0 
115 
31080 
1165 
96.3 
116 
43470 
1470 
96.6 
117 
47040 
896 
98.1 
118 
37065 
511 
98.6 
119 
32890 
441 
98.7 
120 
54495 
2935 
94.6 
121 
10290 
2373 
76.9 
122 
54705 
4106 
92.5 
123 
69990 
1466 
97.9 
124 
21175 
2993 
85.9 
125 
45150 
— 
126 
61005 
4452 
92.7 
127 
01950 
3633 
94.1 
128 
114030 
17042 
85.1 
129 
90090 
8127 
91.0 
130 
6650 
805 
87.9 
Average . 
93.3 
Tubes 71-80, frozen December 16, 1898, in hours; 
thawed December 30, after 2 weeks. Minimal tempera- 
ture, (--14° C ). 
Tubes 81-90, frozen December 17, 1898 in 2 hours; 
thawed December 31, after 2 weeks. Minimal tempera- 
ture, (-8° C.). 
Tubes 111-120, frozen December 23, 1898, in 2 hours ; 
thawed December 30, after 1 week. Minimal temperature 
(-10° C.). 
Tubes 121-130, frozen December 24, 1898, in \\ hours; 
thawed December 31, after 1 week. Minimal temperature, 
(-12° C.). 
Race B. Series III 
Race B. 
Series IV. 
Number 
of Tube. 
Average Number Bacteria per c.c. 
Reduction 
per cent. 
Unfrozen Water. 
Thawed Ice. 
91 
34965 
180 
99.5 
92 
25445 
55 
99.8 
93 
28560 
60 
99.8 
94 
29085 
165 
99.4 
95 
33810 
365 
98.9 
90 
32745 
25 
99.9 
97 
26880 
5705 
78.8 
98 
15855 
15 
99.9 
99 
22330 
75 
99.7 
10© 
90300 
30 
99.9+ 
151 
2560 
2 
99.9 
152 
1595 
4 
99.7 
153 
1555 
— 
— 
154 
— 
— 
— 
155 
225 
1 
99.6 
150 
1195 
4 
99.6 
157 
95 
2 
97.9 
158 
80 
1 
98.8 
159 
30 
0 
100.0 
100 
25 
0 
100.0 
Average . 
98.4 
N umber 
of Tube. 
Average Number Bacteria per c.c. 
Reduction 
per cent. 
Unfrozen Water. 
Thawed Ice. 
41 
70560 
38535 
45.4 
42 
52290 
31605 
39.5 
43 
38640 
28665 
25.8 
44 
48405 
10589 
78.1 
45 
71505 
14458 
79.8 
40 
44100 
10822 
75.4 
47 
63945 
21641 
66.2 
48 
28245 
13541 
52.1 
49 
91035 
19845 
78.3 
50 
27300 
11340 
58.3 
51 
14140 
5740 
59.4 
52 
37800 
25830 
31.7 
53 
29925 
15995 
46.6 
54 
14280 
5810 
59.3 
55 
39710 
16870 
57.5 
50 
27825 
9486 
65.9 • 
57 , 
13685 
5390 
60.6 
58 
12565 
5565 
55.7 
59 
32760 
33075 
0.0 
00 
24570 
9345 
62.0 
Average . . . 
53.8 
Tubes 91-100, frozen December 20, 1898, in 2 hours; 
thawed December 28, after 3 days. Minimal tempera- 
ture, (—12° C.). 
Tubes 151-160, frozen January 3, 1899, in 2 hours; 
thawed January G, after 3 days. Minimal temperature, 
(-12° C.). 
Tubes 41-50, frozen December 1, 1898, in 2 liours; 
thawed December 2, after 2$ hours. Minimal tempera- 
ture, (—7° C.). 
Tubes 51-60, frozen December 8, 1898, in hours; 
thawed December 9, after hours. Minimal tempera- 
ture, (-10° C.). SEDGWICK AND WINSLOW. BACILLUS OF TYFIIOID FEVEK. 
495 
Race B. Series V. 
Race B. 
Series VI. 
Number 
of Tube. 
Average Number 
Unfrozen Water. 
Bacteria per c.c. 
Thawed Ice. 
Reduction 
per cent. 
61 
30135 
13510 
55.2 
62 
23625 
8505 
64.0 
63 
10035 
10430 
46.9 
61 
13055 
12600 
3.4 
65 
21840 
10500 
51.9 
66 
13085 
6720 
50.9 
67 
10800 
10535 
37.3 
68 
12075 
8435 
30.1 
69 
13230 
11130 
15.9 
70 
18025 
12740 
29.3 
101 
32865 
18515 
43.7 
102 
31710 
37275 
0.0 
103 
42525 
5070 
86.7 
101 
32865 
36225 
0.0 
105 
4585 
65 
98.5 
106 
22050 
9380 
57.5 
107 
5280 
184590 
0.0 
108 
5207 
200010 
0.0 
100 
15155 
0 
100.0 
110 
4585 
107740 
0.0 
Average . 
38.6 
Number 
of Tube. 
Average number Bacteria per c. c. 
Reduction 
per cent. 
Unfrozen Water. 
Thawed Ice. 
21 
10 
200 
0.0 
22 
75 
170 
0.0 
23 
190 
70 
63.2 
24 
2695 
3360 
0.0 
25 
100 
250 
0.0 
26 
210 
375 
0.0 
27 
1605 
1505 
6.2 
28 
180 
350 
0.0 
2!) 
1875 
1825 
2.7 
30 
3400 
620 
81.8 
31 
22905 
12040 
47.4 
32 
32655 
8295 
74.6 
33 
18550 
6300 
66.1 
31 
22225 
6125 
72.4 
35 
13755 
4165 
69.7 
36 
15575 
3972 
74.5 
37 
15750 
7490 
52.4 
38 
15470 
3920 
74.7 
39 
19215 
5705 
70.3 
40 
9590 
2610 
72.8 
Average . . . 
41.4 
Tubes 61-70, frozen December 9, 1898, in 2$ hours; 
thawed December 10, after 12 hours. Minimal tempera- 
ture, (-0° C.). 
Tubes 101-110, frozen December 21, 1898, in 1J hours; 
thawed December 22, after 12 hours. Minimal tempera- 
ture, (-8° C.). 
Tubes 21-30, frozen November 28, 1898, in 1$ hours ; 
thawed same day, after S hours. Minimal temperature, 
(—8° C.). 
Tubes 31-40, frozen November 29, 1898, in 1$ hours; 
thawed same day, after 3 hours. Minimal temperature, 
(-8° C.). 
Race B. 
Series VII. 
Race C. 
Series I. 
Numlier 
of Tube. 
Average Number Bacteria per c.c. 
Reduction 
per cent. 
Unfrozen Water. 
Thawed Ice. 
| 
3515 
2080 
40.8 
2 
2180 
3000 
0.0 
3 
3535 
2620 
25.9 
4 
4455 
3105 
30.3 
5 
Control 
Control 
— 
0 
4300 
4325 
0.0 
7 
4075 
3525 
29.1 
8 
3405 
3160 
0.0 
9 
4305 
5970 
0.0 
10 
4G15 
3225 
30.1 
11 
7960 
6300 
20.8 
12 
16380 
14490 
11.5 
lit 
7560 
6860 
9.2 
11 
19460 
21560 
0.0 
i;> 
12215 
10080 
17.5 
10 
21700 
15085 
30.5 
17 
7665 
8400 
0.0 
IS 
13300 
11060 
16.8 
10 
10920 
11340 
0.0 
20 
10360 
14770 
0.0 
Average 
. 13.8 
Number 
of Tube. 
Average Number Bacteria per c.c. 
Reduction 
per cent. 
Unfrozen Water. 
Thawed Ice. 
1 
6580 
— 
— 
2 
13475 
5 
99.9+ 
3 
4795 
7 
99.9 
4 
9310 
4 
99.9+ 
5 
10005 
5 
99.9+ 
6 
10885 
2 
99.9+ 
7 
6230 
102 
98.4 
8 
5215 
0 
100.0 
ft 
10325 
- 
— 
10 
11550 
6 
99.9+ 
21 
120645 
12 
99.9+ 
22 
142065 
16 
99.9+ 
23 
16695 
0 
100.0 
24 
0 
0 
— 
25 
0 
1 
— 
20 
13755 
12 
99.9 
27 
378945 
1 
99.9+ 
28 
101115 
0 
100.0 
2ft 
4370 
2 
99.9+ 
30 
128520 
88 
99.9 
Average . . . 
99.9 
Tubes 1-10, frozen November 19, 1898, in hours ; 
thawed, same day, after 15 minutes. 
Tubes 11-20, frozen November 21, 1898, in 1J hours ; 
thawed, same day, after 15 minutes. 
Tubes 1-10, frozen January 16, 1899, in 1§ hours; 
thawed January 30, after 2 weeks. Minimal temperature, 
(-13° C.). 
Tubes 21-30, frozen January 18, 1899, in If hours ; 
thawed February 1, after 2 weeks. Minimal temperature, 
(-10° C.). 496 
SEDGWICK AND WINSLOW. BACILLUS OF TYFIIOID FEVER. 
Number 
of Tube. 
Average Number Bacteria per c.c. 
Reduction 
per cent. 
Unfrozen Water 
Thawed Ice. 
51 
1920 
2 
99.9 
52 
2675 
2 
99.9 
53 
2200 
1 
99.9+ 
54 
2510 
3 
99.9 
55 
2065 
33 
98.4 
56 
1605 
10 
99.4 
57 
1685 
1 
99.1 
58 
835 
13 
98.4 
59 
460 
15 
96.7 
60 
1820 
- 
— 
71 
6580 
0 
100.0 
72 
7700 
10 
99.9 
73 
2485 
1 
99.9+ 
74 
6440 
1 
99.9+ 
75 
5145 
3 
99.9 
76 
4130 
1 
99.9+ 
77 
3920 
1 
99.9+ 
78 
3080 
4 
99.9 
79 
3535 
0 
100.0 
80 
540 
0 
100.0 
Average . 
99.5 
Race C. 
Series II. 
Race C. 
Seuies III. 
Number 
of Tube. 
Average Number Bacteria per c.c. 
Reduction 
per cent. 
Unfrozen Water. 
Thawed Ice. 
11 
16765 
9 
99.9 
12 
17220 
0 
100.0 
13 
14315 
2 
99.9+ 
14 
900 
2 
99.8 
15 
18270 
3 
99.9+ 
16 
9170 
1 
99.9+ 
17 
G930 
0 
100.0 
18 
7385 
0 
100.0 
19 
2925 
0 
100.0 
20 
9555 
1 
99.9+ 
41 
83475 
6 
99.9+ 
42 
83160 
5 
99.9+ 
43 
64890 
2 
99.9+ 
44 
66570 
4 
99.9+ 
45 
11200 
1 
99.9+ 
46 
21350 
23 
99.9 
47 
2030 
3 
99.9 
48 
700 
1 
99.9 
49 
185 
2 
98.9 
50 
1625 
2 
99.9 
Average . 
99.9 
Tubes 51-60, frozen January 23, 1899, in hours ; 
thawed January 30, after 1 week. Minimal temperature, 
(—12° C.). 
Tubes 71-80, frozen January 25, 1899, in \\ hours; 
thawed February 1, after 1 week. Minimal temperature, 
(-14° C.). 
Tillies 11-20, frozen January 17, 1809, in 1| hours; 
thawed January 20, after 3 days. Minimal temperature, 
(-13° C.). 
Tillies 41-50, frozen January 20, in 2 hours; thawed 
January 23, after 3 dans. Minimal temperature, (—10° C.) 
Race C. 
Series IV. 
Race C. 
Series V. 
Number 
of Tube. 
Average Number Bacteria per c.c. 
Reduction 
per cent. 
Unfrozen Water. 
Thawed Ice. 
01 
3335 
5 
99.9 
02 
3520 
25 
99.3 
63 
195 
10 
94.9 
04 
885 
55 
93.8 
05 
235 
25 
89.4 
00 
215 
60 
72.1 
07 
2105 
10 
99.5 
08 
555 
20 
9G.4 
09 
40 
20 
50.0 
70 
500 
15 
97.0 
81 
1855 
85 
95.4 
82 
1830 
20 
98.9 
83 
200 
55 
78.8 
84 
935 
35 
96.3 
85 
110 
95 
13.6 
80 
3595 
30 
99.2 
87 
4480 
35 
99.2 
88 
315 
70 
77.8 
89 
50 
40 
20.0 
90 
0 
40 
— 
Average . . . 
82.7 
N umber 
Average Number Bacteria per c.c. 
Reduction 
of Tube. 
Unfrozen Water. 
Thawed Ice. 
per cent. 
91 
10710 
20 
99.8 
92 
7280 
75 
99.0 
93 
9555 
90 
99.1 
94 
4045 
5 
99.9 
95 
7735 
35 
99.5 
90 
1570 
355 
77.4 
97 
98 
99 
1325 
20 
98.5 
0440 
590 
90.8 
100 
13090 
10 
99.9 
111 
143040 
5 
99.9+ 
.112 
234300 
105 
99.9+ 
113 
105525 
10 
99.9+ 
114 
41205 
135 
99.7 
115 
11055 
5 
99.9+ 
110 
30855 
20 
99.9 
117 
27195 
40 
99.9 
118 
119070 
50 
99.9+ 
119 
45360 
5 
99.9+ 
120 
15855 
— 
— 
Aver age . . . 
98.0 
Tubes 61-70, frozen January 24, 1899, in hours; 
thawed January 25, after 24 hours. Minimal temperature, 
(-12° C.). 
Tubes 81-90, frozen January 26, 1899, in hours; 
thawed January 27, after 24 hours. Minimal temperature, 
(-13° C.). 
Tubes 91-100, frozen January 27, 1899, in 2 hours; 
thawed January 28, after 15 hours. Minimal temperature, 
(-14° C.). 
Tubes 111-120, frozen February 3, 1899, in 2 hours; 
thawed February 4, after 1.5 hours. Minimal temperature, 
(-15° C.). SEDGWICK AND WINSLOW. — 1JACILLUS OF TYPHOID FEVER. 
497 
Race C. 
Series VI 
Race 1). 
Series I. 
Number 
of Tube. 
Average Number 
Unfrozen Water. 
Bacteria per e.e. 
Thawed Icc. 
Reduction 
per cent. 
31 
350 
10 
97.1 
32 
270 
0 
100.0 
83 
185 
0 
100.0 
34 
90 
5 
94.5 
35 
5 
0 
100.0 
36 
0 
- 
— 
37 
5 
0 
100.0 
38 
20 
0 
100.0 
39 
5 
0 
100.0 
10 
0 
0 
— 
101 
172080 
1 
99.9+ 
102 
61110 
9 
99.9+ 
103 
50700 
1 
99.9+ 
101 
40005 
4 
99.9+ 
105 
10060 
0 
100.0 
100 
140475 
1 
99.9+ 
107 
8855 
1 
99.9+ 
108 
9345 
12 
99.9 
109 
6930 
2 
99.9+ 
no 
5075 
0 
100 0 
Average . 
.... 
99.5 
Ntiinlx-r 
Average Number 
Bacteria per c c. 
Reduction 
of Tube. 
Unfrozen Water. 
Thawed Ice. 
per cent. 
1 
5355 
3080 
42.5 
2 
5915 
3265 
44.8 
3 
(>090 
2405 
59.5 
1 
5070 
070 
88.2 
5 
3010 
1015 
40.3 
6 
4410 
780 
82.3 
7 
3745 
305 
90.3 
8 
3290 
1000 
09.0 
9 
4375 
480 
89.0 
10 
11 
12 
0580 
3040 
44.7 
2380 
95 
90.0 
13 
ll 
l.) 
• — 
— 
— 
7210 
05 
99.1 
Hi 
1855 
40 
97.8 
17 
18 
10 
3675 
90 
97.5 
20 
— 
— 
Average . . 
74.8 
Tu1h‘8 31 40, frozen January 19, 1899, in 2 hours; 
thawed same day, after 8 hours. Minimal temperature, 
(-8° C.). 
Tubes 101-110, frozen February 2, 1899,Jn 2 hours; 
thawed same day, after 8 hours. 
Tubos 1-10, frozen April 27, 18'.)!*, in 2 hours ; thawed 
same day, after 3 hours. Minimal temperature, (—1<>° C\). 
Tubes 11-20, frozen April 28, 181)0, in 2 hours ; thawed 
same day, after 3 hours. Minimal temperature, ( 11° C ). 
Race 1). 
Series II. 
Race D. 
Series TIT. 
Number 
of Tube. 
Average Number Bacteria per c.c. 
Reduction 
per cent. 
Unfrozen Water. 
Thawed Ice 
31 
62005 
318 
99.4 
32 
53235 
5072 
90.5 
33 
77175 
52 
99.9 
31 
5565 
927 
83.3 
35 
184275 
7339 
96.0 
36 
0580 
420 
93.6 
37 
1890 
— 
— 
3S 
62055 
6457 
89.6 
39 
3255 
87 
97.3 
10 
6020 
134 
97.8 
71 
24360 
2 
99.9+ 
72 
29505 
2 
99.9+ 
73 
8925 
22 
99.8 
71 
2430 
0 
100.0 
75 
12810 
4 
99.9+ 
76 
24355 
3 
99.9+ 
77 
9450 
210 
97.8 
78 
2065 
1 
99.9+ 
70 
3160 
1 
99.9+ 
80 
2185 
1 
99.9+ 
Average . 
97.0 
Numl)or 
Average Niiml>er Bacteria jier c.c. 
Reduction 
of Tak«. 
Unfrozen Water. 
Thawed Ice. 
per cent. 
21 
3990 
15 
99.6 
22 
3675 
20 
99.5 
23 
670 
15 
97.8 
24 
ISO 
100 
44.4 
25 
595 
45 
92.4 
20 
2275 
15 
99.3 
27 
180 
20 
88.9 
28 
140 
25 
83.6 
29 
25 
25 
0.0 
30 
240 
0 
100.0 
41 
515 
33 
93.6 
42 
1575 
152 
90.3 
43 
44 
45 
495 
39 
92.2 
1855 
88 
95.3 
40 
47 
2625 
409 
84.4 
48 
49 
7175 
511 
92.9 
50 
1025 
192 
81.3 
Average . . . 
84.4 
Tubes 31 40, frozen May 1, 1890, in 2 hours; thawed 
same day, nfter 6' hours. Minimal temperature, (—10°C.). 
Tubes 71-80, frozen May 8, 1890, in 2 hours; thawed 
same day, after (J hours. Minimal temperature, (—l<i°C.) 
Tillies 21-30, frozen April 28, 1800, in 2 hours: thawed 
April 20, nfter 12 hours. Minimal temperature, (—11° C.). 
Tubes 41-50. frozen May 1, 1890, in 2 hours; thawed 
May 2, after 12 hours. Minimal temperature, (— 10° C.). 498 
SEDGWICK AND WINSLOW. — BACILLUS OF TYPHOID FEVER. 
Race D. 
Series IV. 
Race B. 
Special Series. 
Number 
of Tube. 
Average Number Bacteria per c.c. 
Reduction 
per cent. 
Unfrozen Water. 
Thawed Ice. 
51 
33915 
52 
24570 
106 
99.6 
53 
60795 
33 
99.9 
54 
15960 
35 
99.8 
55 
24805 
89 
99.6 
50 
8820 
103 
98.8 
57 
6860 
6 
99.9 
58 
8960 
55 
99.4 
59 
2660 
29 
98.9 
00 
130410 
199 
99.8 
01 
21735 
32 
99.9 
02 
3200 
71 
97.8 
03 
5215 
5 
99.9 
04 
6160 
63 
99.0 
05 
955 
10 
99.0 
00 
2085 
40 
98.1 
07 
10885 
65 
99.4 
08 
250 
3 
98.8 
09 
790 
34 
95.7 
70 
1150 
23 
98.0 
Average 
99.0 
Number of 
Tube. 
Number Colonies 
per c.c. 
Unfrozen Water. 
Number Colonies 
per c.c. 
Thawed Ice. 
I 
56070 
83790 
0 
0 
II 
55440 
53550 
0 
0 
III 
62370 
61110 
1 
0 
IV 
19320 
21210 
0 
7 
* 
V 
42210 
29190 
0 
0 
VI 
28980 
30030 
0 
0 
VII 
28770 
18060 
1 
0 
VIII 
23730 
33390 
0 
1 
IX 
46410 
42630 
1 
2 
X 
, 
7420 
0 
1 
XI 
13720 
12180 
0 
0 
XII 
22050 
28980 
1 
0 
XIII 
11830 
7700 
0 
0 
XIV 
7980 
7560 
0 
0 
XV 
7070 
6020 
1 
0 
XVI 
6020 
4690 
0 
0 
XVII 
5810 
4690 
0 
0 
XVIII 
1840 
1850 
0 
1 
XIX 
1260 
1510 
1 
0 
XX 
3430 
4200 
0 
0 
Tubes I-X, frozen February 10, 1899, in 4 hours; 
thawed March 10, after 4 weeks. Minimal temperature, 
(-10° C.). 
Tubes XI-XX, frozen February 15, in 1| hours; 
thawed March 15, after 4 weeks. Minimal temperature, 
(-10° C.). • 
Tubes 51-60, frozen May 2, 1899, in 2 hours; thawed 
May 3, after 24 hours. Minimal temperature, (—13° C ). 
Tubes 61-70, frozen May 3, in 2 hours; thawed May 4, 
after 24 hours. Minimal temperature, (—12° C). 
* Colonies in ice of Tube IV proved to be typhoid. Colonies in ice in tubes not starred proved to be contaminations. 
Race C. 
Special Series. 
Number of 
Tube. 
Number Colonies per c.c. 
Unfrozen Water. 
Number Colo- 
nies per c.c. 
Thawed Ice. 
I 
4090 
5390 
0 
0 
II 
G440 
5390 
0 
1 
III 
7140 
5320 
0 
1 
IV 
9870 
12880 
18 
12 
* 
V 
55G0 
7210 
3 
4 
# 
VI 
10080 
11060 
0 
1 
VII 
4060 
3710 
0 
1 
VIII 
4480 
3990 
0 
2 
IX 
1 
1 
0 
0 
X 
1 
2 
1 
- 
XI 
147420 
148050 
0 
- 
XII 
2 
0 
0 
0 
XIII 
G3630 
71190 
0 
0 
XIV 
579G0 
48510 
0 
0 
XV 
87570 
8G940 
1 
0 
Number of 
Tube. 
Number Colonies per c.c. 
Unfrozen Water. 
Number Colo- 
nies per c.c. 
Thawed Icc. 
XVI 
0 
9 
0 
0 
XVII 
21840 
17G40 
0 
0 
XVIII 
9520 
14070 
0 
0 
XIX 
159G0 
8G80 
0 
0 
XX 
7910 
1G170 
0 
0 
XXI 
25410 
30450 
3 
1 
XXII 
34020 
31920 
0 
— 
XXIII 
3 
0 
0 
0 
XXIV 
20790 
17G40 
0 
— 
XXV 
107730 
103950 
272 
2G2 
* 
XXVI 
380 
5G0 
0 
1 
XXVII 
0 
0 
0 
0 
XXVIII 
330 
210 
0 
1 
* 
XXIX 
150 
280 
0 
0 
XXX 
1330 
1440 
0 
0 
Tubes I-X, frozen February 17, 1899, in 3 hours ; XI-XX, February 23, in 2 hours ; XXI-XXX, March 3, in If hours; 
thawed after 1 week in each case. Minimal temperature, —10° C. 
* Colonies in ice proved to be typhoid. Colonies in ice in tubes not starred proved to be contaminations. 499 
SEDGWICK ANI) WINSLOW. — BACILLUS OF TYPHOID FEVER. 
B. EXPERIMENTS ON THE EFFECT OF ALTERNATE FREEZING ANI) THAWING 
UPON THE BACILLI OF TYPHOID FEVER. 
Dr. Prudden, as we have seen, considered intermittent more fatal than uninter- 
rupted freezing, and, indeed, succeeded in one case in entirely sterilizing a tube 
inoculated with 15. typhi by this method. Our four series of experiments on this 
subject were conducted by freezing tubes in the freezer as described in the previous 
section. The tubes of Series I, Race A, were frozen daily for five days and allowed 
to thaw each time after about eighteen hours, samples being planted after each 
thawing. Those of Series I, Race B, were frozen three times, on alternate days, 
remaining frozen for twenty-four hours each time and kept below 2° for the rest of 
the time. The two series in Race D were treated like the tubes frozen for three hours 
and six hours in the last section, except that instead of remaining frozen they were 
thawed and refrozen once and twice respectively during that time. 
The results of these experiments with the results of simple freezing directly com- 
parable are as follows : — 
Frozen once in one day 9G.1 
Frozen twice in two days 98.9 
Frozen three times in three days 99.5 
Frozen four times in four days 99.8 
Race A. 
Reduction. 
Race B. 
Kept frozen for three days (see previous section, Race B, Series III) 98.4 
Frozen twice in four days 99.G 
Kept frozen for seven days (see previous section, Race B, Series II) 93.3 
Frozen three times in six days 99.8 
Rack D. 
Kept frozen for three hours (see previous section, Race D, Series T) 74.8 
Refrozen once in three hours 97.4 
Kept frozen for six hours (see previous section, Race D, Series II) . 97.0 
Refrozen twice in six hours 99.5 
Conclusion. Thawing and refreezing are somewhat more fatal than simple freez- 
ing in its effect on the typhoid bacillus. Four successive freezings and thawings do 
not, however, suffice to kill off the most resistant bacilli. 500 
SEDGWICK AND WINSLOW. — BACILLUS OF TYPHOID FEVEK. 
Number 
of Tube. 
Average before 
Freezing. 
After One Freezing 
After Two Freezings. 
After Three Freezings. 
After Four Freezings. 
Average. 
Reduction 
per cent. 
Average. 
Reduction 
per cent. 
Average. 
Reduction 
per cent. 
Average. 
Reduction 
per cent. 
91 
49910 
- - 
92 
22785 
175 
99.3 
6 
99.9 
1 
99.9 
3 
99.9 
91 
348390 
26320 
92.5 
2495 
99.3 
644 
99.9 
147 
99.9 
95 
308385 
1735 
99.5 
171 
99.9 
59 
99.9 
2 
99.9 
90 
107580 
535 
99.7 
6 
99.9 
2 
99.9 
2 
99.9 
97 
277515 
40 
99.9 
1 
99.9 
3 
99.9 
2 
99.9 
9H 
50820 
745 
98.5 
290 
99.4 
200 
99.6 
120 
99.8 
99 
600 
180 
70.0 
4 
99.3 
1 
99.8 
100 
34090 
190 
99.4 
55 
99.9 
16 
99.9 
8 
99.9 
111 
70895 
380 
99.5 
80 
99.9 
22 
99.9 
20 
99.9 
112 
23875 
685 
97.1 
355 
98.5 
33 
99.9 
13 
99.9 
113 
29750 
— 
— 
— 
114 
38290 
265 
99.3 
40 
99.9 
3 
99.9 
0 
100.0 
115 
31500 
1785 
94.3 
1232 
96.1 
416 
98.7 
427 
98.6 
110 
40585 
75 
99.8 
3 
99.9 
23 
99.9 
3 
99.9 
117 
21 
17 
— 
15 
— 
2 
2 
118 
48335 
4450 
90.8 
3895 
91.9 
2440 
95.0 
119 
38430 
155 
99.6 
11 
99.9 
2 
99.9 
2 
99.9 
120 
25200 
215 
99.1 
14 
99.9 
2 
99.9 
3 
99.9 
Averages 
96.1 
98.9 
99.5 
99.8 
Race A. 
Series I. 
Tubes 91-100, frozen March 28, 1898; thawed and sampled and refrozen, on each of the four days succeeding. Tubes 
remained frozen 18 hours each time. 
Tubes 111-120, treated in same manner week of April 11, 1898. 
Race B. 
Series I. 
Number 
of Tube. 
Average before 
Freezing. 
After One Freezing. 
After Two Freezings. 
After Three Freezings. 
Average. 
Reduction 
per cent. 
Average. 
Reduction 
per cent. 
Average. 
Reduction 
per cent. 
1 
4G950 
420 
99.1 
07 
99.9 
38 
99.9 
2 
22200 
155 
99.3 
24 
99.9 
23 
99.9 
3 
12810 
315 
97.5 
21 
99.8 
19 
99.9 
4 
12145 
215 
98.2 
52 
99.0 
29 
99.8 
5 
10040 
20 
99.8 
10 
99.9 
7 
99.9 
0 
8715 
120 
98.0 
10 
99.9 
5 
99.9 
7 
7945 
80 
99.0 
13 
99.8 
9 
99.9 
8 
4190 
05 
98.4 
13 
99.7 
7 
99.8 
9 
2520 
85 
90.0 
9 
99.0 
4 
99.8 
10 
2450 
95 
90.1 
7 
99.7 
1 
99.9+ 
11 
115290 
775 
99.3 
280 
99.8 
101 
99.9 
12 
142095 
1980 
98.0 
1008 
99.3 
350 
99.8 
13 
183385 
315 
99.8 
90 
99.9 
85 
99.9+ 
14 
74970 
1140 
98.5 
595 
99.2 
354 
99.5 
15 
138915 
480 
99.7 
270 
99.8 
116 
99.9 
10 
227745 
11805 
94.8 
5733 
97.5 
458 
99.8 
17 
104205 
070 
99.4 
198 
99.8 
129 
99.9 
18 
107730 
1250 
98.8 
403 
99.0 
209 
99.8 
19 
103485 
050 
99.0 
139 
99.9 
05 
99.9+ 
20 
120015 
390 
99.7 
171 
99.9 
75 
99.9 
Averages 
98.5 
99.0 
99.8 
Tubes 1-10, frozen April 10, 189!); kept frozen for 24 hours, anil below 2° for 24 hours more; refrozen April 12 and 
April 14. Samples planted before each freezing and April 15. 
Tubes 11-20, treated in same way, April 17, and following days. SEDGWICK AND WINSLOW. BACILLUS OF TYPHOID FEVER. 
501 
Race I). 
Series I. 
Race 1). 
Series II. 
Number 
of Tube. 
Average Number Bacteria per c.c. 
Reduction 
per cent. 
Unfrozen Water. 
Thawed Ice. 
101 
78435 
147 
99.8 
102 
76230 
451 
99.4 
lo:{ 
1765 
23 
98.7 
104 
2730 
47 
98.3 
105 
275 
15 
94.5 
100 
7735 
26 
99.7 
107 
1120 
49 
95.6 
I0S 
11690 
134 
98.9 
100 
6895 
235 
96.6 
110 
— 
— 
— 
m 
— 
— 
— 
132 
— 
— 
133 
3500 
175 
95.0 
134 
— 
— 
— 
135 
29190 
77 
99.7 
130 
20160 
371 
98.2 
137 
6055 
192 
96.8 
138 
5710 
388 
93.2 
139 
— 
— 
— 
140 
3885 
144 
96.3 
Average . . . 
97.4 
Number 
of Tube. 
Average Number Bacteria per c c. 
Reduction 
per cent. 
Unfrozen Water. 
Thawed Ice. 
HI 
34020 
71 
99.8 
112 
59000 
152 
99.7 
113 
13230 
7 
99.9 
114 
32525 
274 
99.2 
115 
1545 
9 
99.4 
lid 
4270 
29 
99.3 
117 
2095 
1 
99.9+ 
118 
6G85 
5 
99.9 
119 
5250 
68 
98.7 
120 
13685 
210 
98.5 
121 
— 
— 
— 
122 
— 
— 
— 
123 
203175 
3 
99.9+ 
124 
40005 
• 1 
99.9+ 
125 
56070 
2 
99.9+ 
120 
* 170100 
297 
99.8 
127 
— 
— 
— 
128 
— 
— 
— 
129 
— 
— 
— 
130 
925 
1 
99.9 
Average . . . 
99.5 
Tubes 101-110, frozen May 5, 1809; thawed ami re- 
frozen in 8 hours. Minimal temperature, (—13° C.)- 
Tubes 131-140, frozen May 13,1899; thawed and re- 
frozen in 3 hours. Minimal temperature, (—19° C.). 
Tubes 111-120, frozen May 9,1899; thawed and refrozen 
twice in next 6 hours. Minimal temperature, (—14° C.). 
Tubes 121-130, frozen May 10,1899; thawed and refrozen 
twice in next 6 hours. Minimal temperature, (-10° C.). 
C. EXPERIMENTS ON THE EFFECT OF TEMPERATURES SLIGHTLY ABOVE THE 
FREEZING-POINT UPON TYPHOID BACILLI IN WATER. 
In these experiments sterilized test tubes were inoculated with pure cultures as in 
all the preceding work. Afterward they were treated in one of three ways, — either 
placed in an incubator at the room temperature, 20' C., or in an ice-chest ranging 
from 8-12°, or cooled in the freezer to a point just above freezing. This last was 
effected by filling the outer chamber with ice without salt. 
In the three sets of tubes treated by the last method at 1°, the duration of expo- 
sure and the reduction were as follows: Race A in two hours was reduced 47.8 per 
cent; Race B in one and one-half hours was reduced 32.9 per cent; Race C in three 
hours was reduced 80.1 per cent. The reductions for the same races actually frozen 
for the nearest corresponding periods, were 73.6 per cent, 41.4 per cent, and 99.5 per 
cent, respectively. Each race maintains its relative position of resistance. The reduc- 
tion in the chilled water is very nearly as great as in the ice; and the difference is 
only what the temperature difference might be expected to produce. Evidently there 502 
SEDGWICK AND WINSLOW. BACILLUS OF TYPHOID FEVER. 
is nothing mysterious about the act of freezing, no mechanical crushing of bacteria ; 
the process of destruction is continuous above and below the freezing-point, depending 
upon the two main factors of time and temperature. 
Series II and III of Races B and C cover longer periods of time and higher tem- 
peratures. Half of the tubes in each series were kept at 10 and half at 20 , but no 
marked differences appeared as the result of these two modes of treatment, and the two 
sets are averaged together in each series. The tubes were kept in these experiments 
for two weeks, one-half of them being sampled on the second and the seventh day, the 
others on the third day and the fourteenth. The tubes were, of course, protected from 
the action of light. 
Race B. 
Race C. 
Time. 
Reduction per cent. 
Series 11. Series III. 
1 day . . 
. . . 92.2 
78.7 
3 days . . 
. . . 99.3 
8G.7 
7 days . . . 
. . 99.9 
99.3 
14 days . . , 
. . . 99.9 
98.8 
Reduction per cent. 
Series II. 
Series III. 
88.4 
71.0 
90.4 
83.8 
94.1 
89.6 
99.9 
99.9 
It will be noted that with each race the second series shows a greater reduction 
than the third. The explanation for this lies in the fact that these experiments were 
carried on some time after the regular experiments on freezing their respective races. 
During the intervening period the germs had been grown on agar, and the first new 
series of experiments with each race showed an extraordinary reduction, over 99 per 
cent in a day, etc. The results of this series have not been tabulated. The second 
series of each race, Series II above, showed more moderate, but still high reductions; 
while by the time the third series was inoculated, a week later, the cultures, by culti- 
vation in bouillon, had regained their normal condition. 
The tubes inoculated with Race D were kept for twenty-four hours only, samples 
being planted after 3, 6, 12, and 24 hours. Series I was kept at 20 and Series II at 10 . 
After 3 hours. 
6 hours. 
12 hours. 
24 hours. 
Series I (20°) . . 
. . . 70.8 
72.6 
85.7 
88.4 
Series II (10°) . . 
. . . 63.1 
74.0 
87.4 
95.5 
Conclusions. From these experiments it appears that typhoid fever bacilli 
behave in water much as they do in ice. A large proportion of them are killed by a 
few minutes’ exposure to the unfavorable conditions; during the next few hours the 
reduction proceeds paripassu with the duration of the experiment; while a few germs 
persist for some time. SEDGWICK AND WINSLOW. BACILLUS OF TYPHOID FEVEIL 
503 
The results differ from those obtained by actual freezing in two respects. We 
have seen that freezing for short periods produced varying and uncertain results, while 
ice over twenty-four hours old showed a constant reduction of over 90 per cent. The 
tubes of water which were not frozen remained subject to this uncertainty for a much 
longer period. Inspection of the tables will show that individual tubes contained some- 
times half of their original germ content after a week, or four-fifths of it after three 
days. On the other hand, complete sterilization ensued more often than in the frozen 
tubes. 
A second characteristic of the viability of the germs in water is the fact, closely 
allied to the first, that an increase seems sometimes to occur. The successive sam- 
plings of the same tube show in certain instances a slight-multiplication. 
The reduction in water at 10 does not seem to be any greater than at 20 . 504 
SEDGWICK AND WINSLOW. BACILLUS OF TYPHOID FEVER. 
Race B. 
Series I. 
Number 
Average Number Bacteria per c.c. 
Reduction 
of Tube. 
Unfrozen Water. 
Thawed Ice. 
per cent. 
131 
1946 
1690 
13.2 
132 
1610 
1001 
37.8 
133 
1848 
1165 
37.0 
134 
1571 
1183 
24.7 
135 
1379 
1155 
16.1 
136 
1291 
1505 
0.0 
137 
1232 
1438 
0.0 
138 
874 
962 
0.0 
139 
892 
1473 
0.0 
140 
1022 
1051 
0.0 
141 
4095 
5 
99.9 
142 
260 
50 
80.8 
143 
205 
90 
56.1 
144 
270 
55 
79.6 
145 
40 
5 
87.5 
146 
215 
145 
32.6 
147 
290 
275 
5.2 
148 
225 
140 
37.8 
149 
215 
120 
44.2 
150 
80 
75 
6.3 
Average . . . 
32.9 
Race A. 
Series I. 
Number 
of Tube. 
Average Number Bacteria per c.c. 
Reduction 
per cent. 
Unfrozen Water. 
Thawed Ice. 
131 
140490 
51450 
63.4 
132 
505 
10 
98.0 
133 
10640 
11410 
0.0 
134 
12390 
6965 
43.8 
135 
31465 
165 
99.5 
136 
273105 
87885 
67.8 
137 
17745 
9870 
44.4 
138 
112770 
63000 
44.1 
111 
254205 
105840 
58.4 
142 
157815 
92610 
41.3 
143 
72135 
42490 
41.1 
145 
302715 
302715 
0.0 
146 
141750 
45990 
67.6 
147 
17360 
21735 
0.0 
Average . 
47.8 
Tubes 131-138, cook'd down to 1°C. in hours, April 
25, 1898. Kept at that temperature for | liour more. 
Tubes 141-147, cooled down to 1° C. in hours, April 
29, 1898. Kept at that temperature for \ hour more. 
Tubes 131-140, cooled down to 0°, without freezing, and 
kept at that temperature for 1| hours. Date, December 
29, 1898. 
Tubes 141-150, cooled down to0°, without freezing, and 
kept at that temperature for 1| hours. Date, January 2, 
1899. 
Rack C. 
Series I. 
Number 
of Tube. 
Average Number Bacteria per c.c. 
Reduction 
Unfrozen Water. 
Thawed Ice. 
per cent. 
121 
55125 
14910 
73.0 
122 
244755 
217350 
11.2 
123 
66465 
11045 
83.4 
124 
62685 
59010 
5.9 
125 
211050 
32760 
84.5 
126 
269955 
75915 
71.9 
127 
103005 
7385 
92.8 
128 
105840 
8085 
92.4 
129 
67725 
20685 
69.5 
130 
23100 
4725 
79.5 
131 
139860 
9660 
93.1 
132 
76545 
3675 
95.2 
133 
58275 
6580 
88.7 
134 
219135 
23205 
89.4 
135 
82530 
3675 
95.6 
136 
84105 
3150 
96.3 
137 
1290 
0 
100.0 
138 
38850 
2105 
94.6 
139 
30030 
860 
97.1 
140 
5530 
640 
88.4 
Average 
. . 80.1 
Tubes 121-130, cooled down to 0° in \ hour, February G, 1899; kept 
at that temperature (not frozen) for three hours. 
Tubes 131-140, cooled down to 0° in | hour, February 7,1899; kept 
at that temperature (not frozen) for 3 hours. SEDGWICK AND WINSLOW. BACILLUS OF TYPIIOII) FEVER. 
505 
Race B. 
Series II. 
Number 
of Tube. 
Average after 
Inoculation. 
After One Day. 
After Three Days. 
After Seven Days. 
After Fourteen Days. 
Average. 
Reduction 
per cent. 
Average. 
Reduction 
per cent. 
Average. 
Reduction 
per cent. 
Average. 
Reduction 
per cent. 
201 
232155 
20 
99.9+ 
2 
99.9+ 
202 
93870 
6755 
92.8 
0 
100.0 
203 
104895 
4515 
95.7 
0 
100.0 
201 
9345 
1180 
87.4 
0 
100.0 
205 
72135 
60 
99.9 
1 
99.9+ 
200 
51660 
0 
100.0 
0 
100.0 
207 
56070 
1837 
96.3 
3 
99.9+ 
208 
1515 
0 
100.0 
0 
100.0 
209 
216405 
2972 
98.8 
21 
99.9+ 
210 
Control 
Con 
trol 
Con 
trol 
211 
11025 
0 
100.0 
1 
99.9+ 
212 
17885 
5075 
71.6 
51 
99.7 
2 IS 
20790 
90 
99.6 
0 
100.0 
211 
10420 
30 
99.7 
0 
100.0 
215 
81270 
2020 
75.2 
73 
99.9 
210 
10640 
1 
99.9+ 
1 
99.9+ 
217 
825 
0 
100.0 
8 
99.0 
218 
170 
1 
99.4 
0 
100.0 
219 
22330 
5 
99.9+ 
0 
100.0 
220 
74340 
623 
99. a 
3 
99.9+ 
A verages 
92.2 
99.3 
99.9 
99.9 
Tube* 201-210, inoculated March 17, 1899; kept in ice-chest at about 10° C. 
Tubes 210-220, inoculated March 17, 1899; kept in room at about 20° C. 
Rack B. 
Series III. 
Number 
of Tube. 
Average after 
Inoculation. 
After One Day. 
After Three Day*. 
After Seven Days. 
After Fourteen Days. 
Average. 
Reduction 
per cent. 
Average. 
Reduction 
per cent. 
Average. 
Reduction 
per cent. 
Average. 
Reduction 
per cent. 
221 
113400 
21630 
80.8 
2407 
97.8 
222 
74340 
385 
99.5 
3 
99.9+ 
223 
74.340 
13405 
82.0 
1043 
98.0 
22+ 
48510 
7840 
83.8 
1043 
97.8 
225 
137025 
2425 
98.2 
0 
100.0 
226 
17535 
1389 
92.1 
0 
100.0 
227 
109685 
40440 
01.0 
0835 
93.4 
22S 
74655 
27405 
03.3 
1003 
97.9 
229 
25200 
2520 
90.0 
28 
99.9 
230 
85050 
7405 
91.2 
112 
99.9 
231 
34050 
5355 
30 
99.9 
232 
18795 
6930 
5 
99.9+ 
233 
7320 
1205 
39 
99.5 
234 
5145 
3420 
9 
99.8 
235 
6565 
1195 
10 
99.7 
236 
5075 
84.5 
22 
99.6 
1 
99.9+ 
237 
10535 
03.1 
312 
97.0 
2 
99.9+ 
23K 
4340 
83.5 
28 
99.3 
3 
99.9 
239 
17955 
33.5 
4284 
70.1 
486 
97.3 
210 
0090 
78.5 
173 
97.2 
3 
99.9+ 
Averages 
78.7 
80.7 
99.3 
98.8 
Tubes 221-230, inoculated March 24, 1899; kept in ice-chest at about 10° C. 
Tubes 231-240, inoculated March 24, 1899; kept in room at about 20° C. 506 
SEDGWICK AND WINSLOW. BACILLUS OF TVPIIOID FEVER. 
Race C. 
Series II. 
Number 
of Tube. 
Average after 
Inoculation. 
After One Day. 
After Three Days. 
After Seven Days. 
After Fourteen Days. 
Average. 
Reduction 
per cent. 
Average. 
Reduction 
per cent. 
Average. 
Reduction, 
per cent. 
Average. 
Reduction 
per cent. 
141 
68985 
1596 
97.7 
30 
99.9+ 
142 
81270 
10206 
87.4 
1043 
98.7 
143 
143640 
1141 
99.2 
56 
99.9+ 
144 
198450 
107730 
45.7 
125956 
36.5 
145 
132300 
1883 
98.6 
38 
99.9+ 
140 
198450 
13041 
93.4 
196 
99.9 
147 
210735 
2142 
99.0 
30 
99.9+ 
148 
80325 
238 
99.9+ 
2 
99.9+ 
149 
82215 
479 
99.9 
2 
99.9+ 
150 
79065 
228 
99.9+ 
0 
100.0 
151 
51345 
1176 
97.7 
2 
99.9+ 
152 
66780 
14238 
78.7 
501 
99.2 
153 
349650 
11970 
96.9 
128 
99.9+ 
154 
73395 
7 
99.9+ 
0 
100.0 
155 
230580 
40761 
82.3 
8347 
96.4 
156 
168210 
135229 
19.6 
54 
99.9+ 
157 
41265 
1400 
96.6 
22 
99.9 
158 
17395 
16 
99.9 
1 
99.9+ 
159 
83790 
3402 
95.9 
5 
99.9+ 
160 
120015 
42 
99.9+ 
3 
99.9+ 
Averages 
88.4 
90.4 
94.1 
99.9 
Tubes 141-150, inoculated March 20, 1899; kept in ice-chest at 10°. 
Tubes 151-160, inoculated March 20, 1899; kept in room at about 20° C. 
Race C. 
Series III. 
Number 
of Tube. 
Average after 
Inoculation. 
After One Day. 
After Three Days. 
After Seven Days. 
After Fourteen Days. 
Average. 
Reduction 
per cent. 
Average. 
Reduction 
per cent. 
Average. 
Reduction 
per cent. 
Average. 
Reduction 
per cent. 
101 
10535 
15 
99.9 
1 
99.9+ 
162 
2G985 
5 
99.9+ 
1 
99.9+ 
163 
44205 
30660 
30.6 
242 
99.5 
164 
5705 
30 
99.4 
0 
100.0 
165 
340 
230 
32.4 
166 
41685 
7497 
82.0 
119 
99.7 
167 
1080 
45 
95.8 
1 
99.9 
16S 
24465 
2709 
88.9. 
14 
99.9 
169 
15330 
15876 
0.0 
170 
Control 
l 
Control 
Con 
trol 
171 
420 
40 
90.5 
0 
100.0 
172 
1205 
805 
33.2 
1 
99.9 
173 
305 
0 
100.0 
1 
99.7 
174 
19740 
9275 
53.0 
609 
96.9 
175 
1065 
310 
70.9 
2 
99.8 
176 
3255 
46 
98.6 
1 
99.9+ 
177 
4105 
271 
93.4 
2 
99.9+ 
178 
1725 
1 
99.9 
0 
100.0 
179 
620 
0 
100.0 
2 
99.7 
180 
17850 
1596 
91.1 
48 
99.7 
Averages 
71.0 
83.3 
89.6 
99.9 
Tubes 161-170, inoculated March 27, 1890; kept in ice-chest at 10°. 
Tubes 171-180, inoculated March 27, 1800; kept in room at about 20° C. SEDGWICK AND WINSLOW. — BACILLUS OF TYPHOID FEVER. 
507 
Race I). 
Series I. 
Number 
of Toko. 
Average after 
Inoculation. 
After Three Houra. 
After Six Hours 
After Twelve Hours. 
After Twenty-four Hours. 
Average. 
Reduction 
per cent. 
Average. 
Seduction 
per cent. 
Average. 
Reduction 
per cent. 
Average. 
Reduction 
per cent. 
Ill 
2590 
30 
98.8 
0 
100.0 
5 
99.8 
5 
99.8 
112 
6670 
25 
99.5 
20 
99.6 
0 
100.0 
5 
99.9 
143 
2315 
5 
99.8 
225 
90.3 
0 
100.0 
10 
99.6 
114 
3185 
140 
95.6 
90 
97.2 
20 
99.4 
0 
100.0 
14ft 
15 
10 
33.3 
15 
0.0 
10 
33.3 
— 
— 
1 16 
340 
70 
79.4 
60 
82.4 
10 
97.1 
25 
92.6 
117 
745 
30 
96.0 
210 
71.8 
5 
99.3 
10 
98.7 
1 IS 
50 
35 
30.0 
0 
100.0 
0 
100.0 
20 
60.0 
119 
45 
30 
33.3 
50 
0.0 
0 
100.0 
5 
88.9 
150 
230 
40 
82.6 
5 
97.8 
5 
97.8 
5 
97.8 
151 
52920 
22890 
56.7 
18690 
64.7 
7969 
84.9 
770 
98.5 
152 
8680 
6300 
27.4 
3780 
56.5 
1761 
80.1 
483 
94.4 
153 
68670 
28350 
58.7 
26885 
60.8 
21168 
69.2 
20097 
70.7 
154 
43155 
715 
98.3 
385 
99.1 
252 
99.4 
119 
99.7 
155 
6650 
1025 
84.6 
380 
94.3 
273 
95.9 
158 
97.6 
Iftft 
41895 
71 ion 
83.3 
7105 
83.0 
5323 
87.3 
4410 
89.5 
157 
74025 
12355 
83.3 
14700 
80.1 
11056 
85.1 
6647 
91.0 
158 
53235 
7980 
85.0 
13125 
75.3 
14647 
72.5 
5386 
89.9 
159 
23205 
6090 
73.8 
9695 
58.2 
8064 
65.2 
10206 
56.0 
160 
3255 
2745 
16.0 
1925 
10.9 
1669 
48.7 
1480 
54.5 
Averages 
70.8 
72.6 
85.7 
88.4 
Tubes 141-150, inoculated May 11, 1899. Kept at room temperature. 
Tubes 151-160. inoculated May 15, 1899. Kept at room temperature. 
Race I). 
Series II. 
Number 
of Take. 
Average after 
Inoculation. 
After Three Hours. 
After Six Hours. 
After Twelve Hours. 
After Twenty-four Hours. 
Average. 
Reduction 
per cent. 
Average. 
Reduction 
per cent. 
Average. 
Reduction 
per cent. 
Average 
Reduction 
per cent. 
Mil 
27015 
7455 
73.9 
5810 
79.0 
— 
— 
6268 
77.3 
162 
291060 
47145 
83.8 
21000 
92.8 
— 
— 
3895 
98.7 
163 
200340 
11235 
43.9 
205 
99.9 
— 
— 
1 
99.9+ 
161 
208530 
24045 
88.5 
10500 
95.0 
— 
— 
5261 
97.5 
165 
178005 
1860 
99.0 
355 
99.8 
— 
— 
21 
99.9+ 
166 
54810 
7000 
87.2 
— 
— 
— 
— 
— 
— 
167 
106785 
11055 
89.1 
2275 
97.9 
— 
— 
1543 
86.4 
16S 
212025 
4130 
98.1 
1385 
99.4 
— 
— 
2001 
99.1 
169 
25095 
1900 
92 2 
745 
97.1 
— 
— 
529 
97.9 
170 
2660 
145 
94.5 
35 
98.7 
— 
— 
129 
95.2 
171 
236250 
95445 
59.6 
78435 
66.8 
25578 
89.2 
3643 
98.5 
172 
240975 
120330 
50.1 
144585 
40.0 
46360 
81.3 
20128 
91.8 
173 
199395 
98595 
50.6 
41840 
79.0 
16065 
91.9 
196 
99.9 
171 
299505 
150255 
49.8 
156200 
47.8 
29578 
90.1 
5691 
98.1 
175 
179550 
104895 
41.6 
54180 
69.8 
9670 
94.4 
2992 
98.3 
176 
107730 
64260 
40.4 
72265 
32.9 
17010 
84.2 
2396 
97.8 
177 
133235 
69930 
47.5 
81900 
38.5 
17(ul 
86.7 
7140 
94.6 
178 
141750 
89515 
36.8 
35700 
74.8 
20790 
85.3 
1101 
99.2 
179 
211080 
220800 
0.0 
158760 
25.0 
56891 
73.1 
31468 
85.1 
iso 
47505 
30765 
35.3 
8610 
71.9 
1141 
97.6 
288 
99.4 
A vent yes 
63.1 
74.0 
87.4 
95.5 
Tubes 161-170, inoculated May 17, 1890. Kept in ice-chest at 10°. 
Tubes 171-180, inoculated May 19, 1899. Kept in ice-chest at 10°. 508 
SEDGWICK AND WINSLOW. BACILLUS OF TYPHOID FEVER. 
1). EXPERIMENTS ON THE VIABILITY OF TYPHOID FEVER BACILLI IN EARTH 
AT VARIOUS TEMPERATURES. 
These experiments were carried on in order to compare the conditions affecting 
a reduction of the number of typhoid bacilli in soil, with those operating on them in 
water and ice. The general method pursued was the same, the inoculation of 
numerous small portions of a sterile medium with a pure culture of the micro- 
organism. In each series of experiments about one hundred grains of sifted clayey 
soil were sterilized by baking for sixteen hours, on two successive days. The whole 
of the earth was then inoculated by mixing with it a bouillon culture two or three 
days old, of B. typhi, Race B; and an even distribution was accomplished by stirring 
and kneading with a spatula. The earth, having been dried by the previous baking, 
absorbed the bouillon culture without becoming visibly damp. Fifty portions of the 
inoculated earth of one gram each were then weighed out and placed in fifty sterile 
empty test-tubes. Of these fifty portions, ten were at once mixed with sterile water 
and two check plates made from each flask. The remaining forty tubes were carried 
to the cold storage warehouse or kept at the room temperature, as the case might be, 
in either condition being protected from the action of light. After one day, three 
days, one week, and two weeks, ten tubes were removed and planted. In every 
case the entire gram of earth was mixed with ten, one hundred or nine hundred cubic 
centimeters of sterile water; and two check plates were made from the dilution. 
The inoculation, weighing and tubing of the earth, were conducted in a glass 
chamber some three feet square, with a sliding door raised only sufficiently to admit 
the arms of the operator. Control plates were made from four portions of the earth 
before inoculation, the portions of a gram apiece being tubed and planted exactly 
like the regular tubes. The following were the results per gram: — 
Colonies per Gram. 
1 
s 
3 
4 
14 
1 
0 
3 
0 
0 
360 
0 
The tubes of the first three series were kept at the cold storage warehouse during 
the period of the experiment, at 0 C. Those of the fourth series were kept at the 
room temperature. The summarized average results of these four series are as 
follows: — SEDGWICK AND WINSLOW. BACILLUS OF TYPHOID FEVEIi. 
509 
Typhoid Bacilli in Earth. Average Number per Gram. 
Series 10°.. 
After Inoculation. 
. . . 180776 
After 1 day. 
4635 
3 days. 
705 
7 days. 
25 
14 days. 
9 
110°.. 
. . . 4846855 
95017 
1395 
525 
588 
Ill 0° . . 
. . . 7778595 
324588 
4656 
1304 
1160 
IV 20° . . 
. . . 4673683 
2565 
450 
95 
92 
Two more series of experiments with earth were carried out to throw light on 
the part played hy dryness in the reduction manifest in the first experiments. In 
these latter researches the sets of fifty tubes were inoculated just as before, and ten 
of them were planted at once. The remaining forty wrere divided into two portions. 
The gram of earth in each of twenty of the tubes was moistened by the addition of 
about one-third cubic centimeter of sterilized tap water; while the earth in the other 
twenty tubes was left in its comparatively dry condition. The tubes were all kept at 
the room temperature. Thus a comparison may be drawn as to the viability of the 
germ in damp and in dry earth. The results were as follows: — 
Typhoid Bacilli in I)ky and Damp Earth. Average Number per Gram. 
After Inoculation. 
After 1 day. 
3 days. 
7 days. 
14 days. 
Series V . . 
. . . 939115 
{Pry 
2070 
50 
2 
47 
( Damp 
225 
7010 
1295 
8 
VI . . 
. . . 1198260 
{Dry 
566 
71 
12 
4 
1 Damp 
1699110 
— 
— 
29587 
Conclusions. 1. The typhoid bacilli in dry earth behave just as in water and 
in ice. They die out, rapidly at first, and their numbers are progressively reduced 
as the treatment is prolonged. A fraction of one per cent persists for some time. 
2. Cold alone does not materially affect the reduction of typhoid germs in dry 
earth. 
3. In moist earth, although the main phenomena are the same, the destruction 
of the bacteria is much less rapid. With the liberal food supply introduced with the 
bouillon in these experiments, they appear sometimes to hold their own entirely. 510 
SEDGWICK AND WINSLOW. DAC1LLUS OF TYPHOID FEVER. 
TYPHOID BACILLI IN EARTH. 
Series I. 
Number 
of Tube. 
February 13, 1899. 
Number 
of Tube. 
February 14, 1899. 
Bacteria 
per gram. 
Bacteria 
per gram. 
1 
233000 
243000 
11 
5400 
1800 
2 
217000 
— 
12 
4500 
4500 
3 
114000 
112000 
13 
7200 
1800 
4 
123000 
120000 
14 
6300 
4500 
5 
504000 
207000 
15 
2700 
3600 
G 
107000 
126000 
IG 
900 
5400 
7 
178000 
141000 
17 
1800 
13500 
8 
157000 
153000 
18 
8100 
9900 
1!> 
3600 
1800 
20 
2700 
2700 
Average 
180776 
Average 
4635 
Number 
of Tube. 
February 1C, 1899. 
Number 
of Tube. 
February 20, 1899. 
Number 
of Tube. 
February 27, 1899. 
Bacteria per gram. 
Bacteria per gram.» 
Bacteria per gram. 
21 
900 
600 
31 
30 
10 
41 
20 
0 
22 
1000 
900 
32 
10 
0 
42 
30 
40 
23 
900 
200 
33 
90 
50 
43 
10 
0 
24 
600 
400 
34 
0 
10 
44 
0 
0 
25 
900 
1600 
35 
0 
0 
45 
20 
0 
20 
900 
400 
36 
30 
0 
46 
20 
0 
27 
400 
700 
37 
0 
80 
47 
0 
0 
28 
300 
400 
38 
30 
70 
48 
0 
30 
29 
900 
800 
39 
10 
40 
49 
0 
0 
30 
400 
700 
50 
0 
0 
Average 
705 
Average 
25 
Average 
9 
Tubes kept at 0° C. SEDGWICK AND WINSLOW. BACILLUS OF TYPHOID FEVER. 
511 
Series II. 
Number 
of Tube. 
February ‘JO, 1890. 
Number 
of Tube. 
February 21, 1899. 
Bacteria per gram. 
Bacteria per gram. 
1 
4932900 
5896800 
11 
130500 
175500 
2 
5040300 
4049400 
12 
103500 
— 
3 
5216400 
4876200 
13 
119700 
81900 
4 
2286900 
470(5100 
14 
55800 
70200 
5 
5953500 
7030800 
15 
54000 
51300 
G 
2570400 
3(528800 
1G 
102600 
— 
7 
5159700 
4309200 
17 
41400 
37800 
S 
6860700 
5443200 
18 
117900 
140400 
9 
3686500 
4989(500 
19 
114300 
115200 
20 
126900 
74700 
A verage 
484(5855 
Average 
95017 
Number 
of Tube. 
February '23, 1899. 
Number 
of Tube. 
February 27, 1899. 
Number 
of Tube. 
March 6, 1899. 
Bacteria per grain. 
Bacteria 
per gram. 
Bacteria per gram. 
21 
1200 
1300 
31 
30 
110 
41 
340 
400 
22 
1400 
1000 
32 
210 
310 
42 
160 
110 
23 
700 
1700 
33 
60 
240 
43 
1770 
750 
24 
500 
1200 
34 
660 
470 
44 
1070 
1600 
25 
1100 
800 
35 
110 
00 
45 
160 
200 
26 
300 
700 
36 
240 
200 
46 
150 
000 
27 
2200 
4000 
37 
310 
500 
47 
120 
800 
28 
2600 
3100 
38 
820 
210 
48 
300 
430 
29 
1100 * 
700 
39 
100 
240 
30 
400 
1000 
40 
2800 
2620 
Average 
1305 
Average 
525 
Average 
588 
Kept at 0° C. 512 
SEDGWICK AND WINSLOW. BACILLUS OF TYPHOID FEVER. 
Series III. 
Number 
of Tube. 
February 24, 1899. 
Number 
of Tube. 
February 25, 1899. 
Bacteria per gram. 
Bacteria per gram. 
1 
8541900 
7144200 
11 
466200 
522900 
2 
6747800 
7200900 
12 
529200 
229500 
3 
7314300 
6066900 
13 
409500 
621100 
4 
10432800 
10092600 
14 
415800 
371700 
5 
7711200 
6917400 
15 
270900 
258300 
6 
6860700 
7597800 
10 
289800 
216900 
7 
7881300 
8278200 
17 
573300 
346500 
8 
8731800 
6577200 
18 
144900 
171100 
9 
6463800 
7711200 
19 
5400 
3600 
10 
9695700 
7994700 
• 
Average 
7778595 
Average 
324588 
Number 
of Tube. 
February 27, 1899. 
Number 
of Tube. 
March 3, 1899. 
Number 
of Tube. 
March 10, 1899. 
Bacteria per gram. 
Bacteria per gram. 
Bacteria per gram. 
21 
1600 
1400 
31 
220 
370 
41 
1710 
420 
22 
2400 
1500 
32 
380 
250 
42 
1390 
350 
23 
6900 
7300 
33 
3710 
370 
43 
1770 
— 
24 
1500 
900 
34 
310 
— 
44 
— 
— 
25 
1600 
2600 
35 
3290 
240 
45 
2870 
2150 
20 
4000 
3600 
36 
5530 
2310 
40 
660 
420 
27 
1900 
1600 
37 
930 
270 
47 
160 
210 
28 
10500 
25200 
38 
690 
480 
48 
1510 
40 
39 
1020 
4410 
49 
1360 
1450 
40 
190 
140 
50 
2420 
1220 
Average 
4656 
Average 
1304 
Average 
1160 
Kept at 0° C. SEDGWICK AND WINSLOW. — BACILLUS OF TYPHOID FEVER. 
513 
Series IV. 
Number 
of Tube. 
February 28, 1809. 
Number 
of Tube. 
March 1 
1880. 
Bacteria per gram. 
Bacteria per gram. 
1 
4139100 
6010200 
II 
10800 
4500 
2 
3742200 
4876200 
12 
2700 
900 
3 
3798900 
2721600 
13 
2700 
1800 
4 
3685500 
— 
14 
900 
900 
5 
5896800 
7144200 
15 
1800 
2700 
6 
5216400 
5556600 
16 
900 
900 
7 
4025700 
3028800 
17 
1800 
900 
18 
900 
0 
19 
5400 
7200 
• * 
20 
1800 
1800 
A vernrje 
4673683 
A verage 
2565 
Number 
of Tube. 
March 3, 1899. 
Number 
of Tube. 
March 7 
1899. 
Number 
bf Tube. 
March 14, 1899. 
Bacteria per gram. 
Bacteria 
per gram. 
Bacteria per gram-. 
21 
900 
1800 
31 
20 
10 
41 
* 10 
0 
22 
900 
0 
32 
20 
30 
42 
140 
380 
23 
0 
900 
33 
GO 
20 
43 
20 
170 
24 
1800 
0 
34 
30 
10 
44 
130 
110 
25 
900 
0 
35 
90 
10 
45 
350 
30 
26 
0 
0 
36 
G90 
60 
46 
1G0 
60 
27 
0 
0 
37 
340 
100 
47 
*40 
0 
28 
0 
900 
38 
120 
20 
48 
40 
20 
29 
0 
0 
39 
250 
0 
49 
190 
0 
30 
900 
0 
40 
10 
10 
A verage 
450 
Average 
95 
Average 
92 
Kept at 20° C. 514 
SEDGWICK AND WINSLOW. BACILLUS OF TYPHOID FEVER. 
Series V. 
AFTER INOCULATION. 
Number 
of Tube. 
March 15, 1899. 
Bacteria per gram. 
1 
1045800 
863100 
2 
1140300 
989100 
3 
16G3200 
1499400 
4 
573300 
938700 
5 
592200 
686700 
6 
1297800 
863100 
7 
1348200 
— 
8 
1004400 
919800 
9 
1026900 
636300 
10 
888300 
875700 
Average 
939115 
DAMP EARTH. 
ri. 
DRY EARTH. 
Number 
of Tube. 
Bacteria per gram. 
Averages. 
Number 
of Tube. 
Bacteria per gram. 
Averages. 
11 
0 
0 
Hi 
• 900 
900 
12- 
900 
0 
17 
9000 
1800 
March 16 
13 
0 
900 
March 1G 
18 
0 
2700 
14 
0 
0 
19 
900 
3600 
225 
20 
0 
900 
2070 
21 
0 
0 
20 
200 
0 
22 
100 
0 
27 
100 
0 
March 18 
23 
21100 
25100 
March 18 
28 
100 
100 
24 
8400 
15000 
29 
0 
0 
25 
400 
0 
7010 
30 
0 
0 
50 
31 
220 
180 
30 
0 
0 
32 
10 
0 
37 
0 
0 
March 22 
33 
3360 
G580 
March 22 
38 
0 
0 
34 
0 
10 
39 
10 
0 
35 
— 
— 
1295 
40 
0 
10 
2 
41 
40 
40 
40 
10 
30 
42 
0 
0 
47 
2G0 
100 
March 29 
43 
0 
0 
March 29 
48 
20 
0 
44 
0* 
0 
49 
20 
0 
45 
0 
0 
8 
50 
10 
20 
47 SEDGWICK AND WINSLOW.- BACILLUS OF TYPHOID FEVER. 
515 
Sekies VI. 
AFTER INOCULATION. 
Number 
of Tube. 
March 29, 1S99. 
Bacteria 
>er gram. 
1 
1455300 
1379700 
2 
1682100 
1455300 
3 
1152900 
1228500 
4 
1083600 
825300 
5 
926100 
1152900 
6 
1304100 
1020600 
7 
1152900 
1568700 
8 
1115100 
1266300 
9 
926100 
1096200 
10 
1398600 
774900 
Average 
1198260 
DAMP EARTII. 
DRY EARTH. 
Number 
of Tube. 
Bacteria per gram. 
Averages. 
Number 
of Tube. 
Bacteria per gram 
Averages. 
n 
1341900 
1266300 
16 
200 
300 
12 
2000100 
1719900 
17 
600 
4200 
1 
March 30 
13 
143G400 
1247400 
March 30 
18 
50 
130 
11 
2891700 
3364200 
ID 
60 
40 
15 
963900 
699300 
1699110 
20 
60 
20 
566 
21 
20 
30 
40 
22 
27 
320 
20 
April 1 
23 
April 1 
28 
70 
40 
24 
29 
— 
— 
25 
— 
30 
0 
50 
71 
31 
36 
0 
0 
32 
37 
10 
10 
April 5 
33 
April 5 
38 
10 
30 
34 
39 
10 
10 
35 
— 
40 
0 
40 
12 
41 
33300 
41400 
46 
10 
12 
42 
900 
0 
47 
6 
5 
April 12 
43 
1800 
1800 
April 12 
48 
— 
— 
44 
88200 
69300 
49 
1 
2 
29587 
50 
1 
4 
4 516 
SEDGWICK AND WINSLOW. BACILLUS OF TYPHOID FEVER. 
E. EXPERIMENTS ON THE EFFECTS OF SEDIMENTATION AND CRYSTALLIZATION 
DURING THE FREEZING OF TYPHOID FEVER BACILLI IN WATER. 
In the experiments under Section I, the reduction effected represented simply the 
death-rate among the bacteria due to the adverse conditions. All the bacteria in the 
unfrozen water which did not perish must, from the nature of the case, be present in 
the thawed ice. In nature, however, the conditions are widely different. Ice is 
formed immediately over and in immediate contact with a large body of water. In 
the water, before and during the process of freezing, the bacteria, being particles 
somewhat heavier than water, continually tend to settle out from the region where 
ice is to form and fall gradually to the bottom. And when the ice formation actually 
takes place, a still more powerful force comes into play. In the process of crystalli- 
zation there is a strong tendency to throw out all substances other than the pure 
compound chiefly concerned. If, then, soluble chemical compounds, other than 
hydrogen monoxide are excluded to a large extent when water freezes, this must 
be still more the case with suspended particles like the bacteria. 
These a priori conclusions are strengthened by the work of Pengra and of the 
Massachusetts State Hoard of Health as well as by common scientific knowledge. 
To test them more carefully with respect to Bacillus typhi abdominalis and Bacil- 
lus coli the following experiments were made. A new wine-cask, of about ten 
gallons capacity, was allowed to stand full of water for a few days in order to remove 
any extractives present. Four pet-cocks were then screwed in, on opposite sides 
of the cask, two about four inches from the top and the others an inch or so from 
the bottom. The whole cask was jacketed with felt so that when placed at a low 
temperature it would freeze from above down and not from the sides inward. It 
was then filled with water, at about the boiling-point, drawn from an ordinary water- 
heater. This water was then allowed to stand for twenty-four hours, when it was 
found cool and still very nearly sterile, containing three or four germs per cubic 
centimeter. The barrel of water was then inoculated by pouring into it a bouillon 
culture of the germ used, the common colon bacillus in the first four experiments, 
the typhoid bacillus, Race B, in the last two. During the course of the experiments 
no sterilization was attempted beyond that partially effected by the boiling water. 
After adding the culture and stirring with a sterile rod, samples were taken from the 
four pet-cocks and planted. The covered cask was then set aside in the room or 
placed on a broad sill just outside the window of the laboratory, where it was exposed SEDGWICK AND WINSLOW. RACILLUS OF TYPHOID FEVER. 
517 
to the winter’s cold. Al ter twenty-four hours of this treatment a thin sheet of ice a 
quarter to half an inch thick was found covering the surface. Samples were again 
taken from the upper cocks just under the ice, and from the lower cocks at the 
bottom of the barrel, and portions of the ice were also planted, being melted in sterile 
bottles, after washing with the water produced by their own melting, according to 
the usual technique. 
Conclusions. 1. These experiments indicate that sedimentation does not produce 
marked or constant effects on colon and typhoid bacilli in water during as short a 
period as twenty-four hours. 
2. On the other hand, the experiments show that ice formed on the surface of a 
quiet body oi water contains only about ten per cent of the bacteria present in the 
water just helow. This difference is probably due to the ph}'sical exclusion by the 
process of crystallization and not to any germicidal action, as the temperature of 
the ice can only differ from that of the adjacent water by a very slight amount. 
There are two distinct forces at work, — the low temperature, killing out germs in 
the ice and water nearly equally, and the crystallizing process extruding germs from 
the ice into the water below. 
REDUCTION OF BACTERIA BY SEDIMENTATION. 
B. Coli. Series I. 
Bacteria per c.c. in samples taken from top and bottom of cask. 
December 29, 1898. 
Averages. 
Top 
00270 
51870 
19320 
18900 
42590 
Bottom 
3570 
3680 
4550 
4310 
4028 
December 30, 1898. 
Top 
11200 
15010 
12390 
10095 
12324 
Bottom 
51030 
44730 
13020 
13580 
30590 
December 31, 1898. 
Top 
7070 
08(50 
5110 
5495 
0132 
Bottom 
51870 
8120 
5845 
40740 
2(5(540 
Kept in room. 
Series II. 
January 3, 1899. 
Averages. 
Top 
120960 
110880 
114660 
101430 
114480 
Bottom 
114030 
97650 
103320 
85050 
100012 
January 4, 1899. 
Top 
51180 
42840 
60910 
56070 
53500 
Bottom 
52920 
47880 
60270 
62160 
56050 
Put outdoors. Temperature —6° to —10° C. Surface did not freeze. 518 
SEDGWICK AND WINSLOW. BACILLUS OF TYPHOID FEVER. 
REDUCTION OF BACTERIA BY SEDIMENTATION AND BY FORMATION OF ICE 
ON FREE SURFACE. 
January 9, 1899. 
Averages. 
Top 
285(50 
21630 
23100 
20370 
23415 
Bottom 
25620 
10010 
32760 
12180 
20142 
January 10, 1899. 
Ice 
370 
250 
550 
670 
460 
1 f T°P 
4620 
4900 
— 
— 
4380 
\ Bottom 
4410 
10360 
7490 
7700 
7490 
B. Coli. Series III. 
Put outside. Temperature —1° C. \ inch ice formed. 
Series IV. 
January 11, 1899. 
Averages. 
Top 
G9930 
62370 
45990 
76860 
63787 
Bottom 
57330 
61110 
68(570 
77490 
66150 
January 12, 1899. 
Ice 
1240 
950 
1890 
780 
1215 
Water 
Top 
15720 
11760 
9870 
8410 
11440 
Bottom 
8820 
10920 
13090 
13020 
11462 
Put outside. Temperature, —15° C. inch ice formed. 
B. Typhi. Series I. 
January 18, 1899. 
Averages. 
Top 
147420 
226800 
198450 
204120 
194197 
Bottom 
247590 
211680 
245700 
153090 
214515 
January 19, 1899. 
Ice 
21840 
28350 
27090 
23940 
25305 
| f Top 
234360 
194670 
147420 
145530 
180495 
is\ Bottom 
209790 
176660 
232470 
181440 
200090 
Put outside, j inch ice formed. 
Series II. 
January 19, 1899. 
Averages. 
Top 
202230 
198450 
156870 
171990 
182385 
Bottom 
154980 
218610 
302400 
254520 
232627 
January 20, 1899. 
Ice 
68040 
75600 
18480 
17430 
44887 • 
| f Top 
270270 
404460 
578340 
319960 
393257 
gs\ Bottom 
307180 
257040 
386820 
238140 
297295 
Put outside. \ inch ice formed. SEDGWICK AND WINSLOW. BACILLUS OF TYBHOID FEVEK. 
519 
IV. DEDUCTIONS FROM THE EXPERIMENTS CONCERNING ICE AS A VEHICLE OF 
INFECTIOUS DISEASE, WITH SPECIAL REFERENCE TO THE PROBLEMS 
OF ICE-SUPPLY AND THE PUBLIC HEALTH. 
Reviewing the several series of experiments described in detail above, and keep- 
ing carefully in mind the conditions under which natural ice is formed, cut, harvested, 
stored, delivered, and finally consumed, as well as those pertaining to the manufac- 
ture, distribution, and consumption of artificial ice, certain conclusions appear to be 
justified concerning ice as a vehicle of disease; and these conclusions are, on the 
whole, decidedly reassuring. 
The conditions which tend naturally to purify polluted waters, are now well under- 
stood. Light, cold and poor food-supply are antiseptic or disinfectant agents of con- 
siderable power; hostile infusoria may devour the living germs of infectious disease; 
the chemical composition of the water may be unfavorable to their survival; and 
gravity may cause them to settle to the bottom, wdiere they may soon perish for want 
of air. The main factor determining the reduction of germs in water is, however, the 
time, — the time during which these and other forces are left to act. Epidemiology 
shows clearly that disease follows best a direct, quick transfer of infectious material 
from patient to susceptible victim; and, if storage of water for some months could 
be insured, many sanitarians would consider such storage a sufficient purification. 
In ice we have this condition realized, — a forced storage of at least weeks and at 
best of many months. At the same time the other effective conditions are also 
heightened. It is no wonder, then, that our experiments show a reduction of over 
99 per cent in typhoid bacilli frozen ; and we may be sure that in nature the 
destruction would exceed, rather than fall short of, such a limit. 
This reduction obtains in tubes which are frozen solid, where there is no chance 
for mechanical exclusion. In natural ice there is another purifying influence. Of 
the germs remaining in the water at the time of freezing, 90 per cent are thrown out 
by the physical phenomena of that process. This reduction is separate from, and 
supplementary to, the disinfecting action of the cold. Accordingly, when both 
factors work together, it is obvious that only one out of a thousand typhoid germs 
present in a polluted stream has a chance of surviving in the ice. 
Under natural conditions the pathogenic germs present in the most highly pol- 
luted stream are comparatively few. Of these few, one-tenth of one per cent may 
be present in ice derived therefrom. But even these scattered individuals are 
weakened by their sojourn under unfavorable conditions, so that, as we have seen, 520 
SEDGWICK AND WINSLOW. — BACILLUS OF TYPHOID FEVEIi. 
they require nearly twice as long for their development as do the normal germs, and 
these few and weakened germs very likely could not produce many, if any, cases of 
typhoid fever, for vitality and virulence in disease germs are probably closely related. 
With artificial ice the case is somewhat different, for such ice is made from water 
frozen solid, and is, as a rule, quickly consumed. Artificial ice, if made from pure 
water, should be above reproach ; but if it be made from water that is impure it 
may contain the germs of infectious disease ; and inasmuch as artificial ice is used 
quickly after its manufacture, the possibility of purification by time is excluded, and 
such ice might therefore conceivably be a menace to the public health. 
With natural ice, as long as absolute sterilization is not effected, there must always 
remain a certain element of doubt, as in the use of sand filters, alluded to above, or in 
the practice of room-disinfection after contagious diseases. The thickness of a layer 
of ice is often artificially increased by cutting holes in it and flooding that already 
formed with the water of the pond. In such a case the effects of crystallization are 
excluded, as in the laboratory tubes. Ice thus formed might be cut at once, and 
served within a week or two ; and in such an exceptional case we cannot say that 
sufficient of the virus might not persist to excite the malady. Yet such an instance 
must be very exceptional; and the general result of human experience, the absence 
of epidemics of typhoid fever traced conclusively to ice, the fact that cities like 
New York, and Lowell and Lawrence in Massachusetts, have used the ice of polluted 
streams, and have yet maintained low death-rates from typhoid fever, all tend to 
support the conclusion at which we have arrived, namely, that natural ice can very 
rarely be a vehicle of typhoid fever. PART II. 
STATISTICAL STUDIES ON THE SEASONAL PREVALENCE OF TYPHOID 
FEVER IN VARIOUS COUNTRIES AND ITS RELATION 
TO SEASONAL TEMPERATURE. 
I. A REVIEW OF THE LITERATURE ON THE SEASONAL PREVALENCE 
OF TYPHOID FEVER. 
The variations in the prevalence of typhoid fever with the changing seasons was 
one of the characteristics of that remarkable disease which struck the very earliest 
observers. Elisha Bartlett, in 1842,(87) wrote of it as follows: “ It is not settled 
whether typhoid fever occurs, with any degree of uniformity, more frequently in one 
season of the year than in another. ... I am sure, however, that, as a general 
rule, its annual prevalence is greatest in the autumn. In New England it is not 
(infrequently called the autumnal or fall fever.” 
Dr. Flint, in 1855,(88) pointed out as one of the points of distinction between 
typhus and typhoid fever that while the former is unaffected by season, the latter 
“ manifests a predilection for the autumnal months, although it is by no means 
restricted in its occurrence to the latter.” Griesinger, a little later,(S9) noted that in 
middle Europe and North America the majority of cases as well as the epidemic out- 
breaks occurred most abundantly in autumn, and that the winter typhoid stood next 
in relative intensity, followed by that of summer, while the fewest cases occurred in 
the spring. He quoted Lombard as authority for the fact that in Geneva the month 
of October shows seven times as many typhoid cases as the month of March. In 
1800, Dr. Tweedie(90) published a table of the admissions of the different forms of 
continued fever into the London Fever Hospital for ten years and brought out an 
interesting contrast between typhoid and typhus fevers. His monthly figures for 
typhoid were as follows : — 
J 
F 
M 
A 
M 
j 
j 
A 
B 
0 
N 
D 
113 
83 
77 
GO 
79 
119 
157 
233 
2G0 
253 
223 
1G1 522 
SEDGWICK AND WINSLOW, — BACILLUS OF TYPHOID FEVER. 
By quarters the difference between the two forms of fever, then just beginning to be 
clearly distinguished, was shown very markedly. 
Quarterly Admissions. 
Typlius Fever. 
Typhoid Fever. 
First Quarter 
1074 
275 
Second “ 
1088 
258 
Third “ 
725 
G50 
Fourth “ 
G19 
G37 
Dr. Tweedie concluded that “ typhus is most prevalent in spring, and the least so 
in autumn, while enteric fever is least prevalent in spring, and most prevalent in 
autumn.” In the same year, Hirsch, in the first edition of the “ Historiscli-geograplii- 
schen Paihologie,” (92) gave an extensive resume of current opinion on the subject. 
He quoted statistics to show that of 519 typhoid epidemics, 168 occurred in autumn, 
140 in winter, 132 in summer, and only 79 in spring. He also printed a table of 
typhoid cases at the hospitals of Lausanne and Geneva, in Lowell and Nassau, and 
of typhoid deaths in the canton of Geneva and the State of Massachusetts, showing 
an autumn maximum and a spring minimum in every case. Summer occupied the 
second place except at Nassau and the canton of Geneva. As to the weather influences 
controlling this prevalence of the disease he quoted very conflicting opinions. While 
Drake and Huss attributed the autumnal fever largely to the summer temperature, 
Davidson and Lombard considered a relatively high humidity as of prime significance. 
Thomson maintained that both factors were of importance, and Seitz, Cless, and Franque 
denied any effect of meteorological conditions. Another review of the seasonal variations 
of typhoid fever was published by Murchison in 1862.(93) He quoted nine English and 
continental authorities as recording the autumnal maximum, and added a table of the 
admissions into the London Fever Hospital which showed a steady rise from April to 
October. Fiedler, in the same year,(94) noted that typhoid fever in Dresden was much 
more abundant in the second half of the year than in the first, and gave the following 
table of typhoid admissions for eleven years. 
Admissions to the Dresden Hospital, 1850-G0. 
J 
F 
M 
A 
M 
j 
j 
A 
s 
0 
N 
D 
123 
7G 
114 
82 
■ 83 
105 
113 
191 
189 
132 
143 
14C SEDGWICK AND WINSLOW. BACILLUS OF TYPHOID FEVER. 
523 
Hie first systematic attempt to show a relation between typhoid fever and defi- 
nite meteorological conditions was made by Haller in 1860.'") This author main- 
tained that the seasonal curve of typhoid corresponded to that of air pressure, and 
that the greatest prevalence was at periods of low temperature, noting, in that con- 
nection, the alleged fact that typhoid fever does not occur autochthonously south of 
the isotherm of 22 C. Haller’s results, however, were not confirmed by other 
observers; and a new theory as to the aetiology of typhoid fever soon took almost 
complete possession of the field. This was the famous ground-water theory of Petten- 
kofer and the Munich school. As applied to typhoid fever this theory was launched 
by Ludwig Buhl in the first article of the first number of the “ Zeitschrift fur Biologie."(95) 
The author dealt with eight hundred and ninety-nine typhoid deaths in a Munich 
hospital during the period 1855-04, and compared, by the graphic method, the 
monthly and yearly variations with the changes in temperature, precipitation, and 
ground-water level. The seasonal curve showed a maximum between December and 
March, culminating in February, and a minimum in August and October. These 
monthly variations, and the fluctuations from year to year, did not correspond to the 
temperature or the precipitation, but did show a certain inverse relation to the height 
of the ground water. 
Seidel(9G) analyzed the figures given by Buhl in a more elaborate manner. He 
compared for each of the one hundred and eight months, from 1856 to 1804, the 
typhoid cases and the ground-water level, using in each case the difference between 
the value for the individual month and the average value for that month during the 
whole period. In 73.5 cases an excess of typhoid fever corresponded with an 
excessive fall of the ground water, and in 34.5 cases the reverse relation obtained. 
Seidel estimated the probability of this preponderance being due to chance alone as 
one to thirty-six thousand. His monthly averages for morbidity are as follows : — 
Typhoid Cases. Munich Hospital. Average, 1856-64. 
J 
F 
H 
A 
M 
j 
j 
A 
s 
0 
N 
D 
14.1 
12.0 
6.9 
5.2 
5.2 
6.0 
4.8 
6.8 
4.2 
7.6 
12.2 
13.1 
In the next year, Seidel(97) analyzed Buhl’s figures in relation to the monthly 
precipitation, again excluding any difference of season per se, by using only the 
differences between the value for a month and the average value for the same month 524 
SEDGWICK AND WINSLOW. — BACILLUS OF TYPHOID FEVER. 
during the nine years considered. He demonstrated a certain inverse relation 
between an excess of precipitation and the prevalence of typhoid fever just as in the 
case of the variation in ground-water level, and considered both factors as of impor- 
tance. Of the fifty-six months in which precipitation and ground-water level varied 
in the same sense, forty-six showed a variation of typhoid morbidity in the opposite 
sense. 
The studies relating to the cases at the Munich Hospital were extended to the 
whole city by Pettenkofer in 1868.(99) He reproduced a chart prepared by F. Wag us, 
which gives by months the typhoid mortality for the whole city from 1850 to 1867 
in comparison with the precipitation and the height of the ground water. The 
seasonal distribution of the disease coincided with that observed at the hospital, the 
average number of typhoid deaths for the whole city being as follows : — 
J 
F 
M 
A 
M 
j 
j 
A 
s 
o 
N 
D 
33.5 
3G.8 
31.8 
23.1 
17.G 
15.2 
15.8 
16.7 
1G.1 
15.0 
19.0 
28.5 
A long series of polemical papers on the relation of typhoid, and more particularly 
of cholera, to the ground water was contributed by Pettenkofer to the “ Archiv fur Ilg- 
giene” and the “ Zeitschrift fur Biologief and his conclusions were finally summarized 
in pamphlet form.(115)’(118) For a time the theories of the Munich school appeared 
to hold the field. Virchow(101) studied the typhoid mortality in Berlin for the period 
1854-71, and concluded that there was a striking inverse relation with the ground- 
water level. Virchow and Guttstadt(114) published curves for Berlin from 1883 to 
1885, which showed a direct relation to the temperature and an inverse relation to 
the ground-water level. Finally, a most elaborate presentation of the facts was made 
by Dr. Soyka in 1887.(117) Like his confreres, this author rested his case in large 
part on the variations in the intensity of the disease and the height of the ground 
water from year to year ; but he also treated of the seasonal variations at some 
length. Although his table of the monthly distribution of the disease in seventeen 
cities, reproduced below, showed an autumnal maximum in all but four cases, he 
considered that these exceptions, Augsburg, Munich, Prague, and Vienna, proved the 
temperature relation to he an indirect one. SEDGWICK AND WINSLOW.—BACILLUS OF TYPHOID FEVER. 
525 
Percentage Monthly Distribution of Typhoid. 
After Soyka. 
Place. 
Period 
Total No. 
j. 
F. 
M. 
A. 
M. 
j. 
J. 
A. 
8. 
0. 
N. 
D. 
' Berlin 
1854-85 
16660 
6.5 
6.0 
5.4 
5.9 
5.9 
5.6 
8.1 
11.0 
12.6 
13.5 
10.6 
8.2 
Neufcbatel ) 
Lausanne J 
1835-52 
933 
8.6 
5.2 
5.5 
2.6 
4.0 
6.1 
7.7 
10.1 
13.4 
17.0 
9.8 
9.4 
Breslau 
1803-78 
2521 
7.7 
7.5 
7.5 
6.4 
6.1 
7.4 
8.5 
9.6 
11.3 
10.5 
8.7 
8.0 
Frankfort-a-M. 
1853-85 
1496 
7.9 
7.1 
6.2 
5.6 
5.8 
6.2 
8.4 
10.6 
11.8 
12.1 
9.0 
8.7 
Hanover 
1874-85 
397 
7.6 
5.1 
6.4 
6.1 
10.0 
7.4 
5.0 
9.1 
12.1 
13.6 
9.6 
8.0 
| Basel 
1826-73 
2213 
8.6 
6.4 
6.1 
5.4 
7.2 
7.6 
8.4 
9.1 
10.7 
10.7 
10.6 
8.7 
Paris 
1867-78 
4152 
6.2 
5.7 
4.6 
4.9 
4.2 
4.9 
6.9 
12.3 
13.4 
12.5 
13.5 
10.3 
Augsburg 
1856-78 
1092 
11.0 
6.7 
8.1 
5.3 
5.1 
5.2 
7.3 
8.9 
9.7 
9.7 
10.6 
10.8 
Bern 
1871-80 
340 
9.7 
6.8 
7.3 
9.1 
6.1 
7.3 
5.8 
6.1 
10.0 
7.9 
12.9 
10.6 
Munich 
1851-85 
7530 
11.5 
11.9 
11.2 
9.0 
7.5 
6.9 
6.4 
6.5 
6.3 
5.8 
6.9 
9.6 
Prague 
1873-84 
998 
10.5 
9.9 
10.2 
8.5 
9.3 
9.6 
9.8 
6.9 
7.1 
5.0 
6.2 
6.8 
Vienna 
1871-85 
4992 
8.2 
7.1 
11.8 
10.1 
9.9 
8.0 
8.1 
7.5 
7.3 
7.3 
6.9 
7.7 
Basel * 
1875-85 
3599 
10.3 
7.1 
8.0 
6.7 
8.0 
8.2 
10.1 
14.8 
8.6 
6.9 
5.7 
4.9 
Leipzig * 
1851-65 
1052 
9.4 
5.7 
5.1 
4.3 
3.8 
6.0 
9.3 
13.0 
12.9 
13.2 
9.4 
7.2 
Copenhagen * 
1842-58 
3198 
6.1 
3.3 
3.2 
2.8 
3.1 
5.0 
7.9 
13.3 
18 3 
16.4 
9.9 
10.2 
Bremen * 
1872-84 
1648 
7.6 
7.0 
6.6 
4.8 
4.9 
4.7 
8.1 
9 6 
13.8 
16.3 
9.1 
7.0 
Chemnitz * 
1838-82 
1455 
6.2 
6.4 
7.3 
5.2 
5.1 
6.9 
7.4 
9 3 
13.2 
13.2 
10.8 
8.0 
Christiania * 
1845-64 
4550 
11.3 
7.3 
6.1 
4.3 
4.0 
3.3 
6.1 
8.8 
8.6 
9.6 
16.8 
13.2 
* Morbidity. Other figures refer to mortality. 
Soyka finally plotted the typhoid fever and ground-water level in Berlin, Frank- 
fort, Bremen, and Munich, and obtained quite regular complementary curves. His 
final conclusion was that “ the rhythm of typhus abdominalis is in general the 
inverted rhythm of the ground-water fluctuations.” 
Unfortunately other researches did not harmonize with these results. Socin at 
Basle (,00) and Fodor at Buda-Pesth(110) found quite different relations between typhoid 
and ground-water level. Later examinations of the yearly variations, even in 
Munich, failed to show the correspondence noted prior to 1881. Most potent of all, 
however, in overthrowing the ground-water theory was the gradual substitution 
of zymotic for miasmatic conceptions of disease which robbed it of any rational, 
setiological basis. 
The only plausible explanation of the connection between ground water and 
typhoid fever, on the basis of the germ theory, had been furnished by Lieber- 
meister,(98) who suggested in 1860 that the phenomena observed by Buhl might simply 
be due to the concentration of soil impurities in wells at the time of low water and 
their transmission in unusually large doses to those who drank therefrom. A simple 
modification of Liebermeister’s idea, including a recognition of the fact that a well in 
use drains a wider area when the ground water is low and is thus liable to pollution 
from more distant sources, has been strongly advocated in this country by Dr. II. B. 
Baker of Michigan. As early as 1878 Dr. Baker(108) published curves showing the 526 
SEDGWICK AND WINSLOW. BACILLUS OF TYPHOID FEVER. 
seasonal distribution of the more important diseases, and pointed out the contrast be- 
tween such diseases as bronchitis, pneumonia, and croup which culminate in the winter 
and the fevers and diarrhoeal diseases which attain a maximum in the hot months. 
His curves showed a slight rise in October for typhoid fever and much more marked 
rises for the classes of “ Typho-malarial,” “Remittent,” and “ Intermittent ” fevers, 
the figures for which in absolute value greatly exceeded those for the former disease. 
Similar tables were published in the succeeding annual reports; and in 1882 it was 
stated that “ more than the average per cent of weekly reports stated the presence 
of typhoid fever in months when the average daily temperature, the average daily 
range of temperature, the absolute humidity of the atmosphere, the monthly and the 
average daily range of the barometer and the average daily pressure of the atmos- 
phere were greater than the average for the year; and less than the average per cent 
of reports stated the presence of typhoid fever in months when these conditions were 
less than the average for the year.” These curves and conclusions have been repeated 
year by year in each annual report, the only change being the gradual increase of 
“typhoid fever” relative to the “typho-malarial” and “remittent” fevers with 
improvement in diagnosis. In 1884, Dr. Baker(m) treated typhoid fever in more 
detail, comparing the seasonal variations of the disease for five years with the height 
of the ground water in Michigan and showing that the disease increased quite regularly 
with the number of inches of earth above the water in the wells. He concluded that “ in 
summer when vegetation is active and not decaying, a lowering of the water is 
uniformly followed by increased prevalence of typhoid fever; with the advent of 
colder weather there is a rise in the water level which is uniformly followed by a 
decreased prevalence of the fever; that this decrease continues through the winter 
and spring even though the level of the well water is lowered, provided the surface 
of the earth is deeply frozen ; that on the contrary high-water level in wells in winter 
and spring coincident with ground not thoroughly frozen is followed by increased 
prevalence of the fever.” 
The relation to ground water was again studied in the Report of the Michigan 
State Board of Health for 1888 (p. lv.), and 1890 (p. 247); and in the Report for 
1894 (p. 300) and succeeding reports, new diagrams were published and the following 
conclusions were added : “ The evidence is conclusive that there is a necessary relation 
between the low water in wells and the sickness from typhoid fever. The fluctuations 
in the sickness from typhoid fever and the depth of the water in wells are nearly 
coincident throughout the several months. The maximum of sickness and the 
minimum of water are coincident in October.” Finally, in 1897, Dr. Baker(128) SEDGWICK AND WINSLOW. BACILLUS OF TYPHOID FEVER. 
527 
printed a new diagram exhibiting the curves of typhoid fever and ground water for 
fourteen years, and suggested in support of his explanation of the inverse relation 
shown that another factor of less universal importance than the pollution of wells by 
distant privies might be the infection of air, food, and drink by germs blown from the 
surface ol the ground, which must be dryer and more exposed to such action when the 
ground water is low. 
Dr. Baker s theory regarding the pollution of wells at times of low water seems quite 
insufficient to account for such a universal phenomenon as the autumnal maximum of 
typhoid fever, even with the additional suggestion as to air contagion. Well water 
is by no means the most important source of the disease; and even as to wells the 
theory does not take all the facts into account. Other observers have attempted to 
trace with some success an almost exactly opposite relation between typhoid fever 
and excessive precipitation. Dr. F. II. Welch,(111) for example, who noted that the 
maximum ot typhoid fever occurred in the last quarter of the year in Malta and in 
Bermuda, in the latter half of the year at Gibraltar, during the autumnal months,— 
iroin March to May, — at the Cape of Good Hope, and in the warm season in India, 
finally concluded that “ the great natural assistant (in the spread of the disease) is the 
rainfall in giving moisture for growth and putrefaction, in causing water circulation 
on the surface and in the subsoil, in its mechanical removal of material from drains 
and hidden receptacles.” 
A\ hatever the explanation, it seems to be proven that at Munich in the period 
studied by Pettenkofer and his followers a real relation did exist between ground-water 
level and typhoid. In no other case, as far as we are aware, has another factor been 
excluded which normally varies inversely with the ground-water level and which does 
bear a plausible relation to the distribution of the typhoid germ. This factor is the 
temperature; and the seasonal curve in many places, Michigan, for example, and 
Berlin, can be more satisfactorily explained by a direct relation to the temperature 
than by an inverse relation to the ground-water level. The first author forcibly to 
call attention to the importance of the temperature factor was Murchison. In the 
second edition of his work on the continued fevers,(102) he gave a table of the monthly 
admissions into the London Fever Hospital from 1848 to 1870, of which the totals 
were as follows : — 
J 
F 
M 
A 
M 
j 
j 
A 
s 
o 
N 
D 
433 
306 
318 
209 
232 
335 
434 
721 
803 
839 
819 
539 528 
SEDGWICK AND WINSLOW.-—BACILLUS OF TYPHOID FEVER. 
Murchison pointed out that a “ great increase of enteric fever in the autumn 
months was observed in each of the twenty-three years, with one noteworthy 
exception (I860).” He also noted that the autumnal increase did not subside 
immediately on the advent of winter, and concluded that “ it would seem as if the 
cause of the disease were only exaggerated or called into action by the protracted 
heat of summer and autumn, and that it required the protracted cold of winter and 
spring to impair its activity or to destroy it.” 
He quoted numerous observers, Todd and Burne in England, Stewart in Scotland, 
Lombard and Rilliet and Barthez in Switzerland, Piedvache, de Claubry and Druher in 
France, Forget and Quincke in Germany, and Bartlett, Wood, and Flint in the United 
States, as recording the autumnal character of the disease. Finally he added, “ Not 
only does enteric fever increase in autumn, but it has been found to be unusually 
prevalent after summers remarkable for their dryness and high temperature, and to 
be unusually rare in summers and autumns which are cold and wet.” The references 
to the early authorities quoted by Murchison will be found in his elaborate 
bibliography. 
Liebermeister also had a clear conception of the possible effect of temperature 
upon the prevalence of typhoid fever. In his article on typhoid fever in Ziemssen’s 
Cyclopedia,(103) he plotted the monthly deaths in Berlin and hospital admissions in 
London and Basle, compared with curves of the monthly variations in temperature, 
and commented on the results as follows: “ The general bearing of these curves is 
evident. The curves representing the frequency of typhoid correspond to the 
curves of average temperature, only with this difference. The different points of the 
typhoid curve follow those of the temperature curve by an interval of some months. 
Fhe minimum of temperature falls in January, that of typhoid in February or April; 
the maximum of temperature falls in July, that of typhoid in September and October. 
It appears, therefore, that the development and spread of typhoid fever is favored 
by the high summer temperature and checked by the low winter temperature. The 
interval of two or three months between the temperature and the typhoid curves 
correspond to the time which is necessary for the changes of temperature to penetrate 
to the places where the typhoid poison is elaborated, for the development of the 
poison without the human body, for the period of incubation, and for the time 
between the commencement of the attack and that of the patient’s admission to the 
hospital, or that of his death.” 
Cousot,(104) in France, about the same time, noted that the month of October always 
showed a maximum of typhoid, that the intensity then diminished till spring, and SEDGWICK AND WINSLOW. BACILLUS OF TYPHOID FLYER. 
529 
that the summer was marked by unimportant oscillations. This influence of the 
season he attributed to the effect of temperature and moisture, and he concluded that 
a moderate temperature accompanied by humidity furnished the conditions most 
favorable for the spread of the disease. Further evidence was contributed by Buchan 
and Mitchell,(106) who tabulated deaths by weeks from all causes distinguished by the 
Registrar-General in London, for thirty years, 1845-74, and for each disease plotted 
a curve showing the average weekly deviation from the general weekly mean. For 
typhoid fever only the six years, 1869—74, were available as prior to 18G9 typhus, 
typhoid and continued fevers were not distinguished. The curve showed a maximum 
in October and November and a minimum from the middle of May to the end of June, 
the rise beginning only at the beginning of July, “when the heat of summer has 
fairly set in.” 
Pistor,(11,,) who compared the typhoid cases and deaths for 1883-85 in Berlin, with 
the height of the ground water and of the river Spree, the precipitation, the height of 
the barometer, and the temperature of the air and the earth, differed from Virchow 
and Cuttstadt (see above) in finding no marked correspondence with the ground-water 
variations. As regards temperature, he concluded that “ typhoid is in general more 
abundant in the hot months than in the cold; it appears, however, that mild and 
damp spring, autumn, and even winter months favor its spread, although not in the 
same degree as the hot season.” Almquist,(119) who studied in detail the seasonal 
prevalence of fourteen diseases in Goteborg, concluded with regard to typhoid fever 
that an annual increase in summer or autumn is characteristic, but that this increase 
is sometimes postponed till the end of the year or the beginning of the next year. 
A second maximum in January is sometimes combined with the summer maximum. 
Dryness and the variation in the ground-water level, and above all the warmth in 
summer and autumn, appeared to him to be operative. Goldberg,(,20) in 1889, made an 
elaborate study of the seasonal prevalence of a large number of diseases in relation 
to various meteorological conditions, and arrived at the conclusion that the weather 
influences the mortality from the infectious diseases both by its effect on the multi- 
plication of the germs and their facilities for entrance into the body and by its effect 
on the vital resistance of the human body in its reaction against the invading organ- 
isms. With regard to typhoid fever he analyzed the statistics for Berlin, Hamburg, 
and Cologne, and summed up his results as follows: — 
A. As regards individual disposition, the extremes of air temperature weaken 
the resistance against typhoid. 
B. As regards time-and-place disposition : 530 
SEDGWICK AND WINSLOW. BACILLUS OF TYPHOID FEVER. 
1. The rise of typhoid morbidity and mortality in Berlin regularly follows the 
rise in the temperature of the earth one-half to one meter below the surface. 
2. The very different annual periods and annual variations in Berlin, Hamburg, and 
Cologne correspond throughout to the rhythm of the movements of the ground water. 
3. The distribution of rainfall in Berlin and Hamburg, if allowance be made for 
evaporation, explains satisfactorily the variations both in the height of the ground 
water and the frequency of typhoid fever. 
Goldberg noted what so many other observers have failed to consider that not only 
the temperature of a given month but also the course of the temperature curve during 
the months immediately preceding, must be considered; thus the same mean monthly 
temperature in May and October need not correspond to the same amount of typhoid. 
He saw that a high temperature favored the spread of typhoid fever, and believed 
that this was due to a lowering of the vital resistance of the human body by extremes 
of temperature. 
The most important evidence bearing upon the relation of heat to the prevalence 
of typhoid fever was that collected by Davidson in his “ Geographical Pathology,’’ 
published in 1892.(122) This author strongly emphasized the seasonal character of the 
disease and considered the temperature to be the one factor of prime importance. 
He stated that in South Australia, Victoria, and New South Wales typhoid attains 
its maximum in the autumn months of March, April, and May, and its minimum in 
September, October, and November. In Queensland the maximum seems to fall 
upon the hot season, from November to February. For India, he concluded that 
in the Bengal Presidency the disease attains its maximum in the second quarter and 
in Central India, Bombay, and Madras in the third quarter. In considering England 
and Germany, he mentioned the usual autumnal maximum; and for several countries 
as quoted below, he gave specific figures as to monthly prevalence. 
Monthly Prevalence of Typhoid Fever. 
Compiled from figures given by Davidson. 
Place. 
Period. 
Number 
Monthly Percentage of Total for Year. 
of Cases. 
j. 
F. 
M. 
A. 
M. 
j. 
j. 
A. 
s. 
0. 
N. 
D. 
Finland 
1889 
639 
3.1 
4.2 
2.8 
2.7 
5.3 
3.1 
11.9 
20.5 
11.7 
12.4 
13.6 
8.6 
France ) 
(Paris) j 
France 
1868-78 
6.2 
5.7 
4.6 
4.9 
42 
4.9 
6.9 
12.3 
13.5 
12.5 
13.6 
10.3 
1886-87 
6.7 
4.2 
4.4 
4.5 
6.5 
7.0 
10.4 
14.6 
14.6 
11.0 
8.2 
7.8 
(Marseilles) j 
Italy 
three years 
6.7 
6.5 
6.8 
7.2 
7.3 
7.2 
9.4 
11.2 
11.1 
10.6 
8.6 
7.4 
Norway 
1886-87 
3138 
11.3 
7.3 
8.9 
8.4 
5.8 
6.1 
7.0 
8.1 
9.5 
10.5 
8.7 
8.4 
Scotland 
t1876-85 
) 
1886-87 
3548 
8.5 
7.7 
7.4 
7.4 
8.8 
7.4 
5.9 
7.4 
9.6 
11.7 
8.7 
9.4 
(principal towns) 
Sweden 
10743 
8.9 
6.5 
6.8 
5.9 
6.3 
5.7 
8.1 
10.3 
11.5 
10.0 
11.2 
8.7 S EDO WICK AND WINSLOW. 11ACILLUS OF TYPHOID FEVER. 
531 
Davidson also attempted to show the causal relation between typhoid fever and 
temperature variations from year to year after the method adopted by Soyka in 
treating of the ground-water theory. In the case of New South Wales he took the 
figures for the period 1877-87, with a mean summer temperature (December to 
February) of 71.14 F., and a mean typhoid death rate of 5.02 per 10,000, and divided 
them to form the two following tables. 
Six Years with Temperature and Typhoid Rate above the Mean for the whole Period 
in»t. 
18T8. 
188*4. 
18S4. 
1885. 
188H. 
Moan Summer Temperature 
Mean Typhoid Death Hate 
71.40 
o.96 
72.00 
6.70 
71.17 
5.66 
71.47 
5.86 
71.87 
5.40 
72.10 
6.03 
Five Years with Temperature and Typhoid Rate below the Mean for the whole Period. 
187tt. 
1880. 
1881. 
1883. 
i88r. 
Mean Summer Temperature 
71.00 
70.17 
70.03 
70.07 
71.10 
Mean Typhoid Death Rate 
3.84 
3.31 
3.50 
4.76 
4.24 
Again, in the case of England, Davidson separated from the period 18C3-87, four 
years in which enteric fever was unusually prevalent, and five years which were 
remarkably free from that disease, and tabulated the relative mean temperatures for 
those years as fo lows: — 
Four Years with Maximum Typhoid. 
Five Years witli Minimum Typhoid. 
Year. 
Difference between Temperature and 
Mean Temperature, 1803-87. 
Year. 
Difference between Temperature and 
Mean Temperature, 1803-87. 
For the Year. 
For the Third 
Quarter. 
For the Year. 
For the Third 
Quarter. 
1867 
-0.7 
-0.7 
1865 
+ 1.0 
+2.1 
1877 
+0.1 
—1.9 
1878 
+0.3 
+0.4 
1879 
-3.1 
-2.3 
1880 
+0.1 
+ 1.0 
1881 
-0.6 
-0.4 
1884 
+ 1.4 
+2.3 
1885 
-0.7 
-1.3 
These investigations of the yearly variations in typhoid fever are of considerable 
interest and should be extended ; but the differences shown by Davidson are so small 
and the material so limited as to preclude the drawing of any general conclusions. 
The clearest and most definite statement of the effect of temperature upon 
the spread of typhoid fever that we have seen was made by Professor Woodhead 
in testifying before the Royal Commission on Metropolitan Water Supply in 
1893.(123) Having spoken of the importance of spring floods in carrying infection into 532 
SEDGWICK AND WINSLOW. — BACILLUS OF TYPHOID FEVER. 
water-supplies, he was asked why the maximum of typhoid occurred in autumn 
instead of at the time of the greatest floods, and his reply was as follows: — 
“You were speaking just now of the conditions under which the typhoid bacillus develops, 
and you were speaking of it as being a pathogenic organism, and therefore as not competing on 
equal terms with the saprophytic organisms •, and here the matter of temperature alone plays 
such a very important part that it cannot be left out of consideration. Although you have in 
February the highest point of floods, you have the temperature so low that the typhoid bacillus 
could scarcely develop under any conditions, whereas when you come to August, when the 
temperature is much nearer that'of the body, that is, the temperature under which the typhoid 
bacillus can exist, then the conditions become so much more favorable that the organism can 
live more readily, more easily, and become more virulent outside the body than it can when the 
temperature is put very much lower, and, therefore, although at flood times the highest flood 
points one would expect (if you leave out the temperature) the typhoid bacillus to do the greatest 
amount of damage, still the temperature is so low that the presence of the bacillus is practically 
a matter of no importance at that period, and it is only when you get to the flood periods when 
the temperature is higher that you can take these statistics as bearing on the point. But beyond 
this, should there be a sporadic case of typhoid due to the use of contaminated water, the conditions 
for the propagation of the disease are not nearly so favorable during the cold months of February 
as they are in the hotter months of the year, and therefore the health returns and the tables 
would be much less affected, not only at the time of the primary outbreak but for some little time 
afterwards.” 
Plausible as the conclusions of Murchison, Davidson, and Woodhead appear, they 
have not gained wide acceptance, and in Germany have been utterly ignored, except 
by Liebermeister in the passage quoted .above. In the same year that his statement 
appeared, Oesterlen (105) published some figures on the quarterly prevalence of typhoid 
as given below, and concluded: “That temperature exerts no, or at least a very 
secondary, influence, is obvious from the very small difference which often appears 
between the different seasons, and from the circumstance that typhoid epidemics may 
arise and culminate at the extremes of temperature, in great cold as well as great 
heat.” 
Quarterly Prevalence of Typhoid. 
After Oesterlen 
Place. 
Period. 
Winter. 
Spring. 
Summer. 
Autumn. 
Geneva 
180 
109 
105 
203 
London 
1849-53 
2813 
2527 
2916 
3305 
Nassau 
1818-56 
670 
470 
486 
863 
Massachusetts 
1845-49 
429 
259 
528 
1132 
Lowell 
1840-47 
130 
102 
163 
250 
Berlin (average monthly deaths) . . . 
1830-38 
27 
18 
23 
41 SEDGWICK ANI) WINSLOW. —BACILLUS OF TYPHOID FEVER. 
533 
A little later, Sander(W7) gave a table showing the quarterly distribution of typhoid 
fever in Berlin, Munich, Halle, Hamburg, Schleswig-Holstein, Dresden, Leipsic, and 
Chemnitz, and stated that the winter in Munich and the autumn in most other places 
is the period of special incidence, while May and June are always the months which 
are most exempt. In 1881, Oldendorff(,09) published a few figures as to quarterly 
prevalence, and repeated Oesterlen’s conclusion as to the limited importance of the 
temperature factor. 
In the second edition of the “ Geographical and Historical Pathology,”(112) Hirsch 
devoted considerable space to a consideration of the meteorological factors affecting 
the spread of typhoid fever. lie quoted first numerous earlier observers, to whom 
references are given in his bibliography. Ziilzer at Berlin and Trier at Copenhagen 
thought that hot and dry weather favored the disease, while others held a wet summer 
to be a contributory cause. Schiefferdecker at Konigsberg, Pribram and Popper at 
Prague, and Jacoby at Breslau believed they had traced a connection between typhoid 
and the ground-water level. Hirsch then gave the very valuable tables of seasonal 
prevalence reproduced below, and in comment remarked, “The result obtained from 
these tables, that the amount of the sickness touches its highest point in autumn, is 
fully borne out by the facts as to the season of greatest prevalence of typhoid in 
many other localities.” He cited Schwerin, Bremen, Iceland, Malta, Italy, the Cape, 
Greenland, and Newfoundland; and added, “ All the more noteworthy is the circum- 
stance that, in tropical and subtropical regions, it is chiefly the hot months that form 
the typhoid season,” quoting Algiers, Tunis, Japan, India, Cochin China, Bermuda, 
and Cuba. An analysis of the typhoid statistics of Berlin from 1871 to 1878 failed 
to show any correspondence between the amount of typhoid in any given year and 
the excess of temperature compared with the mean for the whole period ; and the 
author concluded his consideration of the subject as follows: “That no special 
importance in this connection can be ascribed to the temperature of the air — high 
or low — by itself, follows from the fact that the acme of the disease falls variously in 
various regions within higher latitudes, either in autumn or in winter; while, in the 
tropics, it falls mostly at the time of the greatest heats.” 534 
SEDGWICK AND WINSLOW. BACILLUS OF TYPHOID FEVER. 
Monthly Distribution of Typhoid Fever. 
Months. 
Place. 
Period. 
j. 
j. 
A. 
8. 
0. 
N. 
D. 
j. 
F. 
M. 
A. 
M. 
Christiania* . 
1845-64 
154 
281 
402 
393 
437 
768 
602 
517 
335 
283 
196 
182 
Drammen * . . 
1861-67 
46 
100 
149 
180 
253 
251 
202 
141 
92 
88 
56 
55 
Copenhagen * . 
1842-58 
162 
254 
428 
588 
526 
317 
328 
195 
105 
103 
92 
100 
Hamburg . . 
1873-80 
82 
82 
122 
116 
147 
127 
158 
146 
149 
125 
90 
102 
Berlin . . . 
1854-79 
850 
1159 
1616 
1879 
1965 
1540 
1184 
997 
919 
854 
921 
910 
Breslau . . . 
1863-78 
187 
215 
244 
287 
267 
220 
202 
197 
192 
192 
164 
154 
Leipzig * . . 
1851-65 
64 
98 
137 
135 
144 
99 
76 
100 
60 
54 
44 
41 
Chemnitz * . . 
1837-75 
171 
208 
303 
300 
245 
185 
241 
148 
166 
121 
112 
154 
Prague *. . . 
1874-76 
78 
90 
69 
79 
76 
84 
115 
191 
122 
119 
106 
110 
Nassau* 
1818-59 
1118 
1406 
1742 
2093 
2350 
2207 
1946 
1850 
1584 
1428 
1060 
848 
Frankfort-a-M. 
1863-80 
52 
74 
91 
106 
113 
93 
76 
60 
58 
50 
50 
43 
Stuttgart . . 
1852-77 
69 
76 
83 
87 
88 
108 
122 
106 
84 
90 
73 
66 
Munich . . . j 
1852-68 
1873-79 
J- 408 
377 
379 
365 
363 
425 
619 
718 
783 
699 
548 
444 
Neufchatel ) . 
Lausanne ) . 
1835-52 
57 
72 
95 
125 
159 
92 
88 
81 
49 
52 
25 
38 
Basel . . . 
1824-73 
169 
186 
202 
237 
237 
236 
193 
192 
143 
137 
121 
160 
London * . . 
1848-62 
163 
220 
333 
361 
377 
334 
222 
197 
122 
136 
89 
103 
Glasgow * . . 
1871-79 
12 
15 
30 
43 
36 
31 
20 
23 
18 
29 
18 
17 
Paris .... 
1867-78 
205 
289 
511 
559 
522 
565 
429 
259 
240 
192 
205 
176 
Boston * . . 
1840-47 
30 
47 
86 
92 
98 
60 
48 
39 
43 
40 
21 
41 
Pittsburg . . 
1873-77 
27 
32 
65 
64 
90 
65 
52 
53 
37 
43 
44 
53 
After Hirsch. 
* Hospital admissions. Other figures refer to reported deaths. 
Seasonal Ratio of Typhoid. 
After Hirsch. 
Place. 
Autumn. 
Winter. 
Summer. 
Place. 
Autumn. 
Winter. 
Summer. 
Copenhagen . . 
4.9 
2.1 
2.9 
Geneva .... 
1.9 
1.7 
1.0 
Drammen . . 
3.4 
2.2 
1.5 
Chemnitz 
1 9 
1.4 
1.8 
Lausanne . . 
3.3 
1.9 
1.9 
Basel .... 
1.7 
1.3 
1.3 
London .... 
3.2 
1.7 
2.2 
Glasgow . . . 
1.7 
.9 
.9 
Paris .... 
2.9 
1.6 
1.8 
Pittsburg . . . 
1.5 
1.0 
.9 
Massachusetts 
2.8 
1.3 
1.6 
Breslau .... 
1.5 
1.2 
1.3 
Leipzig .... 
2.7 
1.7 
2.1 
Sweden .... 
1.2 
1.2 
1.1 
Christiania . . . 
2.4 
2.2 
1.3 
Hamburg . . . 
1.2 
1.3 
.9 
Boston .... 
2.4 
1.2 
1.6 
Stuttgart . . . 
1.2 
1.3 
1.0 
Frankfort-a-M. . 
2.2 
1.3 
1.5 
Munich .... 
.7 
1.3 
.7 
Berlin .... 
2.0 
1.2 
1.4 
Prague .... 
.7 
1.3 
.7 
Nassau .... 
2.0 
1.6 
1.3 
These ratios refer to a value of 1 for the Spring Typhoid. Spring is considered to begin with March. SEDGWICK AND WINSLOW. BACILLUS OF TYPHOID FEVER. 
535 
The work which has been done upon the seasonal prevalence of typhoid fever 
within the last ten years has, if anything, only made the subject more obscure. 
Magelssen, in his classic brochure(12,) on the dependence of diseases upon the weather, 
in which he showed so clearly the unfavorable influence of extreme low temperatures 
upon the general mortality, only alluded to typhoid in passing, stating that it is most 
abundant in the latter months of the year. Korosi, in 1894,(124) made an elaborate 
comparison of the reported cases of the infectious diseases in Berlin with the moisture 
and temperature by periods of five days, a week and a month, according to the 
incubation period of the disease. lie criticised those observers, especially Haller, 
who have studied the relation of disease to season, in general, on the ground that such 
a comparison can throw no light on the causation of disease as the phenomena 
involved are too complex. His method consisted in the division of his pentads and 
months into five groups, designated as very cold, fairly cold, fairly warm, warm, and 
hot, and the calculation of the relative prevalence of the disease in each group of 
periods. He thus eliminated all the effects of the weather preceding the period con- 
sidered and obscured the facts. When analyzed into his five temperature groups, two 
maxima appeared, — one in the hot, one in the fairly cold months, — and he concluded 
that no positive relation is shown. Moisture, on the other hand, appeared to exert 
an appreciable effect, and he finally concluded that the maximum of morbidity occurred 
in dry weather with medium warmth, while the minimum was reached when a medium 
temperature coincided with an excess of moisture. Fodor, in 1896,<12,,) declared that 
“ the striking dependence on the warmth, and on the season which is so characteristic 
of cholera is almost entirely wanting in typhoid fever.” In the same year, Jessen(12C) 
published curves which showed the monthly prevalence of measles, croup, and 
diphtheria, typhoid fever, cholera, pneumonia, phthisis, and diarrhoeal diseases of 
children in comparison with variations in wind, temperature, humidity, and rainfall. 
With regard to typhoid fever he concluded that temperature was the only factor 
which affected the disease, and that this was only of slight importance, as typhoid fever, 
though occurring principally in the cold months (!), sometimes attained a maximum 
when the temperature was high. Knoevenagel(127) noted the increased prevalence 
of typhoid fever in Mecklenburg-Schwerin at the end of July and in August and 
September. Berger(,29) and Ruhemann,<130) in 1898, emphasized the importance of 
atmospheric conditions in setiology, and criticised the exclusive attention paid to the 
bacteriological factors in disease. The former author, after an excellent review of 
literature on the influence of weather on various diseases (tuberculosis, pneumonia), 
published curves of morbidity from diphtheria, scarlet fever, measles, and typhoid 536 
SEDGWICK AND WINSLOW. BACILLUS OF TYPHOID FEVER. 
lever in a rural district for a period of four years. Typhoid fever, although the 
total number of cases was only twenty-two, showed a maximum in August and a 
minimum between November and February. Berger concluded that typhoid 
fever is most prevalent with a falling barometer and a rising thermometer, hy- 
grometer, and dew point, and that its occurrence is favored by damp and cloudy 
weather. Ruhemann alluded only in passing to typhoid fever, mentioning its 
summer maximum. Finally, in 1899, Weichselbaum(131) concluded that “no seasonal 
distribution of typhoid, no preference of that disease for any special time of year, 
at least in the marked sense in which it has been shown for cholera, has been, or will 
be demonstrated.”* 
Curschmann, in the latest monograph on typhoid fever,(132) notes that this disease 
shows a “ constant and for many countries a uniform relation to the seasons.” 
“ Everywhere the increased frequency occurs during the late summer and autumn 
months. ’ “ The period of least prevalence of typhoid fever is everywhere the spring 
and the beginning of the summer, especially the months of March, April, and May.” 
lie quotes the figures for London (Murchison), Dresden (Fiedler), and the Hamburg 
epidemic of 1886-87, and gives a table for Leipsic which is reproduced below. The 
London and Leipsic figures, when plotted, show very regular curves. 
Cases of Typhoid Fever received into Jacobsspital, Leipsic, from 1880 to 1892. 
J 
F 
M 
A 
M 
j 
j 
A 
s 
0 
N 
D 
122 
96 
97 ‘ 
78 
71 
75 
136 
252 
240 
193 
150 
88 
In commenting on these facts Curschmann says: “The causes for this remarkable 
uniformity in the relations of typhoid fever to season are as yet wholly unknown. 
* Behrens (Einjfuss tier Witterung auf Diphtherie, ScJiarlach, Maseru und Typhus, Arch. f. Hyg., XL., 1901, 1) 
has recently published an exhaustive study on the influence of weather on the prevalence of diphtheria, scarlet 
fever, measles, and typhoid. His method consists in the arrangement of the individual months for a period of 
five years in classes according to temperature, humidity, and precipitation, and the tabulation of the morbidity 
and mortality for the various classes of months. The cities treated are Carlsruhe, Berlin, Bremen, and Breslau. 
A series of tables is appended of morbidity in Carlsruhe from the four diseases treated by five-day periods with 
an elaborate analysis of the meteorological conditions. The results of the investigation are conflicting and incon- 
clusive. With reference to typhoid fever, Dr. Behrens sums up the evidence from his own work and that of Jessen 
and Korosi as follows: “ Typhoid reaches its maximum in hot weather at Carlsruhe, Berlin, and Breslau, in cold 
weather at Hamburg, and in weather of medium warmth at Budapest. At Bremen no influence of temperature 
can be shown. Carlsruhe, Berlin, Breslau, and Budapest agree in the fact that the number of typhoid cases is 
greatest when the humidity is least; in Bremen, on the other hand, the maximum occurs when the hygrometer is 
highest. A heavy precipitation and a maximum of rainy days favor the disease in all cases.” His final conclusion 
with regard to this disease is as follows: “Typhoid cases are as numerous with a warmer as with a cooler 
temperature, but are markedly favored in their occurrence by cloudy and rainy weather.” SICDGWICK AND WINSLOW. BACILLUS OF TYPHOID FEVER. 
537 
The universality of the relation, its recurrence in all possible, remotely situated regions, 
indicate that it is dependent not upon local, but upon general conditions, possibly 
% 
such as are responsible for the power of multiplication and the vital activity of the 
typhoid germ itself. Although much is known with regard to the details in this con- 
nection, an insight into the solution of general questions is wanting, particularly the 
relation of the poison to important cosmic conditions. It is, therefore, better for the 
present to leave a glaring deficiency rather than to bridge it over with unstable 
theories.” 
II. STATISTICAL STUDIES BY TIIE AUTHORS ON SEASONAL VARIATIONS 
IN TEMPERATURE ANI) ON TIIE PREVALENCE OF TYPHOID 
FEVER IN VARIOUS COUNTRIES. 
It appears, then, from a review of the literature that, although most observers 
have noted a characteristic seasonal distribution of typhoid fever, others, including 
some of those who have written most recently, have denied the existence of such 
regular variations. Of those who realized that the variations did exist, a few sought 
au explanation in the factor of temperature. Their views did not, however, gain 
acceptance, as the evidence furnished was insufficient; and the common view, among 
medical men and sanitarians, has been that the fall maximum of typhoid fever was an 
unexplained phenomenon. 
The bacteriological work on the effect of low temperatures upon the bacillus of 
typhoid fever, reported in the first section of this paper, lent force to the idea that 
the temperature really might in itself exercise a direct effect upon the aetiology of 
this disease. We therefore determined to see whether the relation shown by Mur- 
chison, Liebermeister, and Davidson for a few places could be demonstrated by a more 
exact examination of statistics collected from a wider field. 
We have, accordingly, brought together statistics of the monthly variations in tem- 
perature and in the prevalence of typhoid fever for thirty communities, as follows: 
'fhe States of New York and Massachusetts, the District of Columbia, and the cities 
of Atlanta, Baltimore, Boston, Charleston, Chicago, Cincinnati, Denver, Mobile, 
Newark, New Orleans, New York, Oakland, Philadelphia, St. Paul, and San Francisco, 
in the United States ; the city of Montreal in Canada ; the cities of Berlin, Dresden, 
Leipsic, London, Munich, Paris, and Vienna in Europe; the Empire of Japan, and 
the British Army in India, in Asia; and the cities of Buenos Ayres and Santiago de 
Chile in South America. Four continents and both hemispheres are thus represented, 
and a very wide range of climate. (See pp. 540-566.) 538 
SEDGWICK AND WINSLOW. BACILLUS OF TYPHOID FEVER. 
The mean monthly temperatures for the American cities were obtained from the 
reports of the United States Weather Bureau; those for the German cities, from 
the publications of the astronomical observatories in their respective districts; and 
those for London, Paris, Montreal, Buenos Ayres, and Santiago from special local 
publications mentioned in connection with the tables. For the States of New York 
and Massachusetts, it was assumed that the temperature of New York City and Boston 
would serve without serious error. For Japan, where the range of temperature is 
rather wide, an average was taken of the record of ten stations in different parts of 
the Empire, as given by the Central Meteorological Observatory. In the case of India, 
it appeared inadvisable to attempt to calculate an average for the whole empire, as the 
seasons in the different districts are so very different. The typhoid figures are, there- 
fore, compared with two sets of temperature values, for Central India, and for the 
Punjab, taken from Hann’s “ Klimatologiewhich give a fair idea of the two most 
important meteorological zones. For each of the cities and stations, with one or two 
exceptions, the figures for ten years .have been used in order to secure a reliable 
average; and the mean monthly temperatures finally obtained have all been reduced 
to the Fahrenheit scale for uniformity and convenience in plotting the curves. 
The typhoid statistics include records of hospital admissions at the two hospitals 
of Santiago de Chile, of hospital admissions in the British Army in India, of reported 
cases at Newark and of deaths in all other instances. The figures for the American 
States and cities, for Montreal, London, and Paris, were obtained from the published 
reports of the local Departments of Health, supplemented in some cases by informa- 
tion furnished in reply to correspondence; the German statistics were taken from the 
“ Verojfentlichungen des Kaiserlichen Gesundheitsamtes for Japan, the Annual Reports 
of the Central Sanitary Bureau, for India, the Parliamentary blue-books, and for the 
South American cities, local sanitary periodicals referred to in the tables, were con- 
sulted. The figures for ten years were averaged in each case except as follows: for 
Vienna and Japan the period was five years; for Atlanta, six years; for Montreal 
and New Orleans, eight years; for Denver and Paris, nine years; for the Army in 
India, eleven years; for Buenos Ayres, twenty-two years. In each case the average 
number of deaths per month has been reduced to a ratio of one hundred deaths per 
year, the final figure for each month representing the number that occur in that 
month for every hundred deaths in the year. Thus the absolute amount of the 
disease is entirely eliminated, and only its seasonal distribution considered. The value 
of the statistics will not therefore be impaired by errors of registration, which it may 
be assumed will not vary from month to month. SEDGWICK AND WINSLOW.— BACILLUS OF TYPHOID FEVER. 
539 
Finally, the monthly values for temperature and typhoid prevalence have been 
plotted on the appended plates in order to show graphically the relation of the two 
curves. For each locality the abscissae represent the successive months, and the ordi- 
nates the monthly temperature and percentage of annual typhoid. We should not, 
however, expect the effect of January temperatures to be manifest in the typhoid 
death-rate until March, as about two months will be taken up in the transfer of the 
infection to the victim, in the incubation of the disease, and in its course toward a 
fatal termination. Accordingly, in order to make the relation of the two curves more 
striking, the typhoid curve has in each case been shifted along to the left by just two 
months, so that March typhoid comes just above January temperature, and so on. 
Where cases and not deaths have been considered (Santiago, Newark, India) the curve 
has been only moved along by one month. This transposition does not, of course, 
alter the shape of the curves or their relation to each other, but only makes that 
relation clearer to the eye. (See Plates I.-VIII.) 540 
SEDGWICK AND WINSLOW. — BACILLUS OF TYPHOID FEVER. 
BOSTON. 
Monthly Typhoid Deaths. 
From Reports, Local Department of Health. 
Year. 
j. 
F. 
M. 
A. 
M. 
j. 
j. 
A. 
8. 
o. 
N. 
D. 
1888 
7 
5 
5 
11 
3 
11 
11 
19 
31 
42 
17 
18 
1889 
6 
7 
7 
7 
9 
12 
17 
35 
33 
23 
17 
13 
1890 
7 
5 
7 
7 
7 
8 
9 
20 
27 
20 
19 
19 
1891 
8 
4 
11 
9 
8 
4 
7 
14 
29 
29 
15 
16 
1892 
2 
5 
7 
7 
9 
6 
6 
15 
18 
29 
18 
15 
1893 
13 
9 
6 
10 
13 
12 
7 
15 
14 
26 
17 
6 
1894 
3 
5 
5 
7 
7 
4 
4 
18 
30 
27 
20 
11 
1895 
8 
3 
6 
7 
11 
8 
9 
26 
28 
26 
13 
18 
1896 
14 
6 
2 
5 
6 
7 
8 
13 
30 
34 
23 
14 
1897 
14 
7 
9 
11 
8 
9 
10 
25 
27 
22 
18 
13 
Average 
8.1 
5.6 
6.5 
8.1 
8.1 
8.1 
8.8 
20.0 
26.7 
27.8 
17.7 
14.3 
Ratio of 100 
5.1 
3 5 
4.1 
5.1 
5.1 
5.1 
5.5 
12.5 
16.7 
17.4 
11.1 
8.9 
Mean Monthly Temperature. 
Year. 
j. 
F. 
M. 
A. 
M. 
j. 
j. 
A. 
s. 
0. 
N. 
D. 
1888 
20 
28 
32 
42 
52 
67 
68 
69 
59 
47 
43 
34 
1889 
3G 
26 
38 
48 
60 
69 
69 
67 
63 
48 
45 
38 
1890 
32 
33 
35 
46 
57 
64 
71 
70 
63 
51 
42 
26 
1891 
31 
32 
34 
48 
56 
65 
69 
70 
67 
52 
41 
40 
1892 
28 
28 
33 
48 
56 
70 
73 
70 
62 
53 
41 
30 
1893 
21 
27 
34 
44 
56 
65 
71 
70 
60 
55 
42 
30 
1894 
30 
27 
42 
47 
58 
69 
74 
68 
65 
.54 
38 
32 
1895 
29 
25 
35 
46 
60 
67 
69 
71 
66 
50 
45 
36 
1896 
25 
29 
32 
47 
60 
66 
72 
71 
62 
50 
46 
30 
1897 
28 
31 
37 
49 
58 
62 
72 
70 
63 
54 
41 
34 
Average 
28 
29 
35 
46 
57 
66 
71 
70 
63 
51 
42 
33 
From “ Monthly Weatiier Review,” U. S. Weather Bureau. SEDGWICK AND WINSLOW. BACILLUS OF TYPHOID FEVER. 
541 
NEW YORK CITY. 
Monthly Typhoid Deaths. 
From Reports, State Board of Health. 
Tear. 
j. 
F. 
M 
A. 
M. 
j. 
j. 
A. 
s. 
o. 
N. 
D. 
1887 
28 
13 
21 
11 
11 
16 
33 
51 
53 
38 
26 
22 
1888 
12 
14 
13 
1 1 
23 
11 
35 
42 
82 
52 
37 
33 
1889 
27 
15 
21 
18 
15 
19 
31 
71 
57 
57 
40 
21 
1890 
20 
28 
13 
12 
11 
11 
31 
49 
64 
49 
34 
29 
1891 
14 
11 
17 
13 
20 
23 
28 
57 
65 
56 
51 
29 
1898 
15 
25 
17 
19 
23 
23 
52 
53 
57 
55 
31 
30 
1893 
22 
19 
29 
25 
29 
23 
21 
35 
42 
70 
41 
26 
1894 
' 22 
11 
17 
18 
11 
14 
28 
42 
57 
46 
32 
28 
1895 
17 
16 
8 
14 
13 
23 
27 
37 
46 
48 
37 
36 
- 1896 
20 
17 
11 
12 
10 
13 
25 
42 
38 
39 
34 
36 
Average 
19.7 
16.9 
16.7 
15.3 
16.6 
17.6 
31.1 
47.9 
56.1 
51.0 
36.3 
29.0 
Ratio of 100 
5.6 
4.8 
4.8 
4.2 
4.8 . 
5.1 
8.7 
13.5 
15.8 
14.4 
10.1 
8.2 
Monthly Temperature. 
From “Monthly Weather Review,” U. S. Weather Bureau. 
Year. 
j. 
F. 
M 
A. 
M. 
j. 
j. 
A. 
s. 
0. 
N. 
D. 
1888 
20 
32 
32 
48 
58 
71 
70 
72 
63 
49 
45 
34 
1889 
38 
28 
41 
52 
62 
70 
73 
71 
66 
52 
47 
41 
1890 
40 
40 
37 
51 
01 
70 
73 
72 
67 
55 
46 
31 
1891 
35 
37 
38 
52 
60 
70 
71 
74 
70 
54 
44 
42 
1892 
30 
33 
35 
50 
59 
72 
75 
74 
66 
55 
43 
31 
1893 
23 
30 
30 
48 
59 
69 
75 
74 
64 
58 
44 
35 
1894 
35 
30 
44 
50 
61 
71 
76 
73 
70 
57 
42 
37 
1895 
30 
25 
30 
48 
59 
70 
71 
74 
70 
51 
46 
37 
1890 
28 ' 
30 
32 
50 
64 
66 
73 
73 
65 
52 
48 
32 
1897 
29 
33 
39 
49 
59 
65 
73 
71 
65 
5G 
44 
36 
Average 
31 
32 
37 
50 
60 
69 
73 
73 
67 
54 
45 
36 542 
SEDGWICK AND WINSLOW. BACILLUS OF TYPHOID FEYER. 
MASSACHUSETTS. 
Average Weekly Typhoid Deaths for each Month. 
From Reports, State Board of Health. 
Tear. 
J. 
F. 
M. 
A. 
M. 
j. 
j. 
A. 
s. 
0. 
N. 
D. 
1886 
6 
5 
4 
5 
3 
3 
4 
10 
15 
16 
11 
10 
1887 
4 
8 
8 
7 
6 
7 
5 
14 
22 
16 
12 
7 
1888 
• 6 
5 
6 
7 
5 
6 
5 
10 
16 
26 
11 
8 
1889 
6 
8 
7 
5 
6 
6 
7 
15 
18 
16 
13 
8 
1890 
6 
7 
5 
4 
5 
5 
4 
9 
16 
14 
18 
15 
1891 
15 
11 
7 
7 
4 
2 
4 
6 
14 
15 
11 
9 
1892 
6 
5 
7 
4 
5 
5 
6 
9 
11 
37 
11 
12 
1893 
9 
8 
5 
6 
5 
5 
4 
9 
13 
17 
11 
10 
1894 
5 
7 
4 
5 
6 
2 
4 
7 
16 
15 
15 
9 
1895 
4 
2 
5 
6 
5 
5 
5 
12 
16 
12 
10 
11 
Average 
6.7 
6.6 
5.8 
5.6 
5.0 
4.6 
4.8 
10.1 
15.7 
18.4 
12.3 
9.9 
Ratio of 100 
6.4 
6.3 
5.5 
5.3 
4.7 
4.4 
4.5 
9.6 
13.9 
17.4 
11.7 
9.4 
NEW YORK STATE. 
Monthly Typhoid Deaths. 
From Reports, State Board of Health. 
Year. 
j. 
F. 
M. 
A. 
M. 
j. 
j. 
A. 
8. 
o. 
N. 
D. 
1887 
72 
57 
72 
56 
37 
54 
102 
194 
248 
182 
149 
104 
1888 
64 
84 
81 
45 
59 
45 
73 
174 
279 
288 
153 
138 
1889 
89 
71 
69 
78 
63 
45 
117 
224 
247 
261 
169 
117 
1890 
117 
94 
72 
73 
72 
69 
101 
167 
234 
240 
216 
157 
1891 
138 
127 
121 
103 
88 
90 
97 
171 
287 
290 
241 
183 
1892 
116 
98 
96 
77 
71 
75 
131 
182 
282 
205 
184 
147 
1893 
120 
101 
115 
111 
93 
83 
87 
157 
227 
253 
180 
158 
1894 
105 
86 
131 
94 
85 
72 
93 
183 
229 
234 
189 
139 
1895 
108 
99 
99 
115 
92 
81 
108 
156 
220 
265 
204 
169 
1896 
158 
121 
103 
87 
59 
66 
103 
171 
221 
195 
132 
126 
Average 
109 
94 
96 
84 
72 
68 
101 
178 
247 
241 
182 
144 
I Ratio of 100 
6.7 
5.8 
5.9 
5.2 
4.5 
4.2 
6.3 
11.0 
15.3 
14.9 
11.3 
8.9 SEDGWICK AND WINSLOW. —BACILLUS OF TYPHOID FEVER. 
543 
ST. PAUL.'’ 
Monthly Typhoid Deaths. 
Year. 
i. 
Fk 
M. 
A. 
M. 
j. 
J. 
A. 
8. 
o. 
N. 
D. 
1888 
7 
8 
4 
5 
6 
4 
6 
14 
27 
29 
22 
10 
1890 
7 
4 
2 
5 
0 
2 
2 
17 
11 
6 
6 
3 
1891 
3 
6 
4 
1 
2 
3 
2 
6 
12 
10 
7 
5 
1892 
2 
1 
6 
1 
0 
0 
2 
1 
4 
12 
7 
11 
1893 
3 
2 
1 
0 
2 
3 
1 
11 
8 
9 
5 
6 
1894 
0 
1 
1 
1 
0 
2 
2 
4 
6 
5 
6 
4 
1895 
3 
5 
3 
1 
1 
3 
4 
5 
2 
8 
1 
2 
1896 
7 
6 
3 
3 
1 
1 
0 
5 
0 
4 
5 
2 
1897 
0 
2 
2 
2 
1 
1 
0 
1 
3 
3 
6 
1 
Average 
3.6 
3.9 
2.9 
2.1 
1.4 
2.1 
2.1 
7.1 
8.1 
8.4 
7.2 
4.9 
Ratio of 100 
6.6 
7.2 
5.4 
3.9 
2.7 
3.9 
3.9 
13.2 
15.1 
15.7 
13.4 
9.1 
From Reports, Local Board of Health. 
Mkan Monthly Temperature. 
Prom “ Monthly Weather Review,” U. S. Weather Bureau. 
Ye»r. 
j. 
F. 
M. 
A. 
M. 
j. 
3. 
A. 
8. 
0. 
N. 
D. 
1888 
-1 
12 
18 
40 
50 
67 
72 
66 
55 
43 
33 
24 
1889 
20 
10 
37 
48 
56 
64 
71 
70 
59 
45 
29 
29 
1890 
10 
18 
22 
48 
52 
70 
72 
65 
58 
46 
36 
24 
1891 
21 
11 
23 
48 
58 
65 
66 
67 
66 
48 
26 
27 
1892 
10 
21 
28 
42 
51 
65 
71 
69 
63 
51 
28 
15 
1893 
3 
9 
23 
39 
54 
71 
73 
69 
62 
49 
30 
12 
1894 
10 
14 
35 
49 
58 
72 
76 
72 
64 
49 
27 
27 
1895 
6 
11 
28 
52 
59 
67 
70 
70 
65 
44 
31 
21 
1896 
16 
21 
25 
47 
63 
68 
71 
70 
56 
45 
22 
23 
1897 
9 
19 
24 
46 
57 
64 
74 
66 
68 
53 
29 
15 
Average 
10 
15 
27 
46 
V 
56 
67 
72 
68 
62 
47 
29 
22 544 
SEDGWICK AND WINSLOW. — BACILLUS OF TYPHOID FEVER. 
DENVER. 
Monthly Typhoid Deaths. 
From Reports, Local Department of Health. 
Year. 
J. 
F. 
M. 
A. 
M. 
j. 
j. 
A. 
s. 
0. 
N. 
D. 
1888 
8 
1 
3 
0 
2 
5 
14 
22 
24 
31 
21 
3 
1889 
4 
0 
1 
1 
4 
1 
14 
23 
51 
55 
22 
12 
1890 
7 
5 
2 
1 
9 
7 
17 
• 31 
56 
72 
50 
30 
1891 
13 
9 
4 
3 
2 
3 
6 
11 
15 
17 
9 
7 
1892 
2 
1 
2 
3 
2 
6 
2 
12 
9 
9 
15 
1 
1893 
4 
4 
0 
5 
8 
5 
8 
4 
5 
10 
15 
3 
1894 
4 
2 
1 
1 
3 
6 
3 
8 
8 
7 
48 
8 
1895 
5 
1 
2 
1 
2 
2 
2 
5 
8 
6 
8 
2 
1896 
5 
0 
2 
1 
4 
0 
6 
13 
28 
17 
12 
3 
Average 
5.8 
2.6 
1.9 
1.8 
4.0 
3.9 
8.0 
15.4 
22.7 
24.9 
22.2 
7.7 
Ratio of 100 
4.8 
2.1 
1.6 
1.5 
3.3 
3.2 
6.7 
11.9 
18.9 
20.7 
18.5 
6.4 
Mean Monthly Temperature. 
From “ Monthly Weather Review,” U. S. Weather Bureau. 
Year. 
j. 
F. 
M 
A. 
M. 
j. 
j. 
A. 
s. 
0. 
N. 
D. 
1888 
27 
39 
33 
53 
53 
68 
71 
65 
61 
48 
34 
34 
1889 
27 
30 
43 
51 
55 
64 
72 
73 
60 
52 
32 
40 
1890 
28 
34 
41 
48 
58 
68 
72 
69 
62 
49 
40 
39 
1891 
25 
27 
32 
48 
56 
63 
70 
69 
64 
52 
38 
31 
1892 
26 
33 
36 
46 
51 
65 
72 
71 
66 
50 
43 
27 
1893 
38 
31 
38 
45 
54 
69 
73 
70 
63 
51 
39 
38 
1894 
31 
25 
40 
50 
59 
66 
72 
71 
63 
54 
45 
32 
1895 
28 
27 
37 
50 
56 
62 
67 
70 
66 
51 
38 
34 
1896 
37 
38 
37 
50 
59 
68 
72 
72 
61 
50 
36 
39 
1897 
27 
31 
36 
47 
61 
65 
70 
70 
66 
51 
41 
28 
Average 
29 
31 
37 
49 
56 
66 
71 
70 
63 
51 
39 
34 SEDGWICK AND WINSLOW. BACILLUS OF TYPHOID FEVER. 
545 
MONTREAL. 
Monthly Typhoid Deaths. 
Year. 
j. 
F. 
H. 
A. 
M. 
j 
j. 
A. 
s. 
0. 
N. 
D. 
1888 
5 
2 
4 
2 
4 
4 
4 
20 
24 
14 
G 
5 
1889 
3 
3 
2 
3 
2 
2 
3 
15 
19 
8 
G 
6 
1891 
0 
0 
8 
1 
2 
2 
4 
7 
13 
10 
8 
7 
1892 
4 
G 
3 
0 
1 
2 
4 
6 
8 
12 
15 
4 
1893 
G 
3 
2 
4 
4 
3 
5 
2 
6 
8 
2 
5 
1894 
6 
3 
4 
5 
3 
0 
1 
6 
6 
1 
6 
1 
1895 
1 
2 
1 
2 
5 
2 
4 
3 
10 
6 
5 
3 
1896 
3 
3 
2 
2 
3 
1 
7 
4 
4 
9 
4 
4 
Average 
3.5 
2.7 
3.2 
2.4 
3.0 
2.0 
4.0 
7.9 
11.2 
8.5 
G.5 
4.4 
Ratio of 100 
5.9 
4.6 
5.5 
4.0 
5.1 
3.4 
6.7 
13.3 
18.9 
14.3 
10.9 
7.4 
From Reports, Local Department of Health. 
Mean Monthly Temperature. 
From Reports, Local Department of Health. 
Year. 
j 
F. 
M. 
A. 
M. 
j. 
j. 
A. 
s. 
0. 
N. 
D. 
1888 
4 
12 
23 
37 
54 
66 
68 
64 
55 
40 
33 
23 
1891 
15 
19 
27 
40 
52 
64 
69 
65 
58 
46 
32 
7 
1892 
15 
17 
26 
42 
52 
65 
66 
67 
62 
45 
35 
30 
1893 
15 
18 
23 
41 
53 
66 
70 
66 
57 
46 
33 
19 
1894 
13 
13 
32 
45 
56 
66 
69 
63 
60 
49 
30 
23 
1895 
15 
14 
22 
41 
58 
70 
67 
66 
60 
41 
34 
22 
1896 
12 
15 
20 
41 
58 
65 
69 
67 
57 
43 
35 
18 
Average 
13 
15 
25 
41 
55 
66 
68 
65 
58 
44 
33 
20 546 
SEDGWICK AND WINSLOW. BACILLUS OF TYPHOID FEVER. 
BALTIMORE. 
Monthly Typhoid Deaths. 
From Reports, Local Department of Health. 
Year. 
j. 
F. 
M. 
A. 
M. 
j. 
j. 
A. 
8. 
0. 
N. 
D. 
1888 
7 
8 
6 
6 
5 
10 
4 
26 
34 
21 
17 
17 
1889 
15 
7 
14 
4 
12 
16 
8 
30 
26 
14 
19 
26 
1890 
10 
12 
15 
19 
13 
13 
29 
36 
30 
34 
25 
11 
1891 
15 
8 
3 
5 
9 
6 
9 
14 
22 
29 
17 
13 
1892 
13 
9 
8 
9 
11 
8 
16 
30 
26 
29 
21 
13 
1893 
20 
5 
11 
10 
4 
13 
23 
33 
32 
27 
34 
12 
1894 
12 
8 
6 
14 
14 
8 
18 
39 
28 
31 
21 
23 
1895 
11 
11 
6 
9 
7 
3 
24 
12 
27 
31 
19 
13 
1896 
7 
11 
4 
11 
11 
13 
19 
23 
29 
28 
22 
10 
1897 
7 
8 
6 
6 
6 
8 
13 
36 
36 
27 
19 
17 
Average 
12.7 
8.9 
7.9 
9.3 
9 2 
9.8 
16.3 
27.9 
29.0 
27.1 
21.4 
15.5 
Ratio of 100 
6.6 
4.6 
4.1 
4.8 
4.8 
5.1 
8.4 
14.4 
15.0 
14.0 
11.1 
8.0 
Mean Monthly Temperature. 
From “Monthly Weather Review,” U. S. Weather Bureau. 
Year. 
j. 
F. 
M. 
A. 
M. 
j. 
j. 
1 
A. 
s. 
0. 
N. 
D. 
1888 
29 
35 
37 
53 
63 
73 
74 
75 
64 
51 
47 
36 
1889 
39 
31 
43 
55 
66 
71 
77 
74 
66 
54 
48 
46 
1890 
44 
43 
42 
54 
64 
75 
75 
74 
68 
57 
48 
35 
1891 
38 
41 
39 
56 
62 
71 
72 
74 
71 
55 
44 
44 
1892 
32 
37 
37 
52 
63 
76 
76 
76 
66 
56 
44 
33 
1893 
25 
34 
40 
53 
61 
72 
77 
75 
67 
57 
44 
39 
1894 
37 
34 
48 
52 
65 
73 
78 
73 
71 
57 
43 
38 
1895 
31 
26 
41 
53 
62 
74 
73 
77 
72 
53 
47 
39 
1896 
34 
36 
38 
57 
69 
71 
78 
76 
68 
55 
51 
36 
; 1897 
32 
37 
45 
53 
63 
70 
77 
74 
69 
58 
46 
39 
Average 
34 
35 
41 
54 
64 
73 
76 
75 
68 
55 
46 
38 SEDGWICK AND WINSLOW. BACILLUS OF TYPHOID FEVER. 
547 
LONDON. 
Weekly Typhoid Deaths and Average Mean Temperature. 
1. 
2. 
3. 
4. 
5. 
0. 
7. 
8. 
9. 
10. 
n. 
12. 
13. 
Deaths 
13 
14 
13 
11 
12 
7 
10 
9 
9 
9 
9 
7 
8 
Temperature 
38 
38 
38 
39 
40 
39 
40 
40 
41 
41 
42 
42 
45 
14. 
15. 
io. 
17. 
18. 
19. 
20. 
21. 
22. 
23. 
24. 
25. 
20. 
Deaths . . . 
9 
6 
8 
7 
8 
7 
9 
8 
8 
7 
9 
9 
9 
Temperature 
4G 
46 
48 
48 
50 
52 
54 
56 
57 
58 
59 
60 
61 
27. 
28. 
29. 
30. 
31. 
32. 
33. 
34. 
35. 
30. 
37. 
38. 
39. 
Deaths 
8 
10 
7 
9 
10 
9 
13 
12 
19 
15 
16 
17 
17 
Temperature 
62 
63 
63 
62 
62 
63 
62 
61 
60 
59 
58 
56 
55 
40. 
41. 
42. 
43. 
44. 
45. 
40. 
47. 
48. 
49. 
50. 
51. 
52. 
Deaths 
17 
19 
19 
18 
20 
19 
19 
20 
17 
16 
19 
15 
16 
Temperature 
53 
51 
49 
47 
47 
45 
42 
41 
41 
41 
40 
39 
38 
From the Weekly Returns of the Registrar-General. 
Weekly typhoid rate is average for ten years, 1888-1897. Temperature is average for years, 1840-1890. 
Average Weekly Typhoid Deaths for each Month. 
j. 
F. 
M. 
A. 
M. 
j. 
j. 
A. 
s. 
o 
N. 
D. 
Deaths 
13.0 
9.0 
8.0 
7.0 
8.0 
8.0 
8.0 
16.0 
16.0 
18.0 
19.0 
16.0 
Rat io of 100 
8.9 
6.2 
5.5 
4.8 
5.5 
5.5 
5.5 
11.0 
11.0 
12.3 
13.0 
11.0 
Temperature . . 
38.0 
40.0 
42.0 
47.0 
53.0 
59.0 
62.0 
62.0 
57.0 
50.0 
43.0 
40.0 
LEIPSIC. 1/ 
Monthly Typhoid Deaths. 
From “ VeroffuntlichunKen des Kaiserliclien Gesundlieitsamtes.” 
j. 
F. 
M. 
A. 
M. 
j. 
j. 
A. 
B. 
o. 
N. 
D. 
1888 
1 
2 
1 
1 
l 
3 
2 
1 
1 
0 
4 
2 
1889 
2 
2 
2 
2 
l 
0 
4 
6 
6 
6 
3 
2 
1890 
6 
1 
1 
0 
l 
5 
2 
7 
6 
4 
3 
6 
1891 
5 
5 
4 
6 
5 
1 
6 
5 
6 
4 
3 
4 
1892 
0 
3 
1 
0 
1 
1 
4 
3 
4 
7 
3 
2 
1893 
2 
2 
0 
0 
0 
3 
4 
1 
6 
2 
1 
6 
1894 
1 
2 
2 
1 
5 
5 
4 
3 
2 
4 
5 
4 
1895 
0 
3 
1 
1 
2 
2 
0 
3 
8 
5 
6 
2 
1896 
2 
3 
2 
5 
1 
1 
1 
3 
2 
2 
3 
7 
1897 
3 
5 
3 
1 
2 
1 
2 
5 
8 
3 
4 
0 
Average 
2.2 
2.8 
1.7 
1.7 
1.9 
2.2 
2.9 
3.7 
4.9 
3.7 
3.5 
3.5 
Ratio of 100 
6.3 
8.1 
4.9 
4.9 
5.5 
6.3 
8.4 
10.7 
14.1 
10.7 
10.1 
10.1 
Mean Monthly Temperature. 1864-1890. 
From “ Amtliclie Publication des Kiinigl. sachsischen meteorologisehen Institutes. Das Klima des Kdnigreiches 
Sachsen.” Heft III, 1805. 
J. 
F. 
M. 
A. 
M. 
J. 
j. 
A. 
a. 
o 
N. 
D. 
Centigrade 
-1 
0 
8 
8 
13 
17 
18 
17 
14 
8 
3 
0 
Fahrenheit 
.‘50 
82 
87 
46 
55 
63 
64 
63 
57 
46 
37 
32 548 
SEDGWICK AND WINSLOW. — BACILLUS OF TYPHOID FEVER. 
BERLIN. 
Monthly Typhoid Deaths. 
From “ Veroffentlicliungen des Kaiserlichen Gesundlieitsamtes.” 
Year. 
j. 
F. 
M. 
A. 
M. 
J. 
j. 
A. 
s. 
o. 
N. 
D. 
1888 
38 
19 
10 
11 
8 
10 
18 
22 
13 
15 
11 
13 
1889 
11 
21 
58 
23 
14 
11 
28 
20 
23 
18 
36 
27 
1890 
14 
15 
11 
9 
10 
8 
10 
16 
18 
18 
9 
5 
1891 
9 
7 
16 
7 
9 
9 
7 
20 
19 
31 
20 
12 
1892 
12 
6 
15 
7 
10 
10 
7 
9 
23 
15 
10 
13 
1893 
7 
6 
11 
8 
13 
8 
7 
19 
42 
16 
18 
5 
1894 
7 
9 
8 
7 
7 
5 
7 
5 
10 
10 
5 
12 
1895 
6 
7 
8 
2 
4 
14 
8 
16 
22 
17 
8 
14 
1896 
9 
6 
6 
11 
8 
6 
11 
14 
17 
11 
4 
5 
1897 
3 
1 
8 
8 
5 
4 
4 
20 
11 
10 
7 
9 
Average 
11.6 
9.7 
15.1 
9.3 
8.8 
8.5 
10.7 
16.1 
19.8 
16.1 
12.8 
11.5 
Ratio of 100 
8.0 
6.7 
10.0 
6.0 
6.0 
5.3 
7.3 
10.7 
13.3 
10.7 
8.7 
7.3 
Mean Monthly Temperature. 
From “Ergebnisse der meteorologischen Beobachtungen von dem Kdniglich. Preussischen meteorologischen Institut.” 
Year. 
j. 
F. 
M. 
A. 
M. 
j. 
j. 
A. 
s. 
o. 
N. 
D. 
1888 
—1 
-2 
0 
■ 7 
14 
17 
17 
17 
15 
8 
4 
2 
1889 
-2 
—1 
1 
9 
19 
22 
18 
17 
13 
9 
4 
0 
1890 
3 
—1 
6 
9 
16 
16 
18 
19 
15 
9 
4 
-4 
1891 
-3 
1 
4 
6 
15 
16 
18 
17 
16 
11 
4 
3 
1892 
—1 
1 
2 
8 
13 
17 
18 
20 
16 
9 
2 
—1 
1893 
-7 
2 
5 
9 
13 
17 
19 
18 
13 
11 
3 
1 
1894 
—1 
3 
6 
11 
13 
16 
20 
17 
12 
9 
5 
1 
Average 
—2 
0 
3 
8 
15 
17 
18 
18 
14 
9 
4 
0 
Fahrenheit 
28 
32 
37 
46 
59 
63 
64 
64 
57 
48 
39 
32 SEDGWICK AND WINSLOW. BACILLUS OF TYPHOID FEVER. 
549 
EMPIRE OF JAPAN. 
Monthly Typhoid Deaths. 
From Annual Iie|>ort8 of the Central Sanitary Bureau of Japan. 
Year. 
j. 
r. 
M. 
A. 
M. 
j. 
j. 
A. 
s. 
0. 
N. 
D. 
1890 
568 
386 
380 
402 
540 
527 
603 
838 
1159 
1309 
977 
775 
1891 
556 
285 
264 
392 
724 
1038 
1028 
940 
1255 
1286 
1009 
837 
1892 
541 
382 
366 
405 
468 
628 
734 
938 
1165 
1252 
921 
729 
1893 
508 
361 
368 
340 
450 
520 ‘ 
646 
827 
1190 
1262 
1016 
695 
1894 
515 
319 
226 
2o0 
338 
515 
681 
1068 
1298 
1141 
995 
702 
Average 
538 
347 
321 
359 
504 
646 
738 
922 
1203 
1250 
984 
748 
Ratio of 100 
6.3 
4.1 
3.8 
4.2 
5.9 
7.5 
8.6 
10.8 
14.1 
14.6 
11.5 
8.8 
Mean Monthly Temperature. (10 stations.) (3-6 years.) 
From “ The Climate of Japan,” Central Meteorological Observatory, Tokio, 1893. 
Stations. 
j 
F. 
M. 
A. 
M. 
j. 
j. 
A. 
s. 
0. 
N. 
D. 
Kumamoto 
3 
7 
10 
16 
19 
22 
26 
27 
25 
18 
12 
8 
Matsuyama 
4 
6 
8 
13 
17 
21 
25 
26 
23 
17 
12 
9 
Hiroshima . 
3 
5 
8 
13 
19 
22 
25 
27 
23 
17 
11 
7 
Ozaka . 
4 
5 
9 
14 
18 
22 
26 
27 
24 
17 
12 
7 
Wakayama 
5 
5 
9 
14 
18 
22 
26 
27 
23 
17 
12 
8 
N agano 
-2 
0 
4 
11 
14 
19 
23 
24 
20 
12 
7 
4 
Tokio . 
3 
4 
7 
13 
16 
21 
24 
26 
22 
16 
11 
6 
Hakodate . 
-4 
-2 
3 
7 
11 
14 
18 
21 
18 
11 
5 
1 
Sapporo 
—7 
-5 
0 
5 
11 
15 
19 
21 
17 
9 
3 
-1 
Nemuro 
-6 
—5 
-1 
4 
7 
10 
15 
18 
16 
10 
4 
0 
Average 
0 
2 
6 
11 
15 
19 
23 
24 
21 
14 
9 
5 
Fahrenheit 
32 
36 
43 
52 
59 
66 
74 
75 
70 
58 
48 
41 550 
SEDGWICK AND WINSLOW. BACILLUS OF TYPHOID FEVER. 
SAN FRANCISCO. 
Monthly Typhoid Deaths. 
From Reports, Local Department of Health. 
Year. 
j. 
F. 
M. 
A. 
M. 
j. 
j 
A. 
s. 
0. 
N. 
D. 
1888 
12 
10 
18 
13 
15 
12 
1889 
6 
10 
8 
13 
12 
9 
1890 
17 
6 
7 
6 
4 
17 
17 
13 
11 
21 
14 
10 
1891 
13 
6 
10 
5 
9 
8 
18 
16 
7 
8 
11 
12 
1892 
8 
6 
8 
4 
4 
1 
13 
14 
5 
13 
11 
7 
1893 
4 
5 
3 
4 
3 
12 
10 
11 
10 
9 
16 
10 
1894 
11 
7 
5 
5 
9 
6 
8 
13 
12 
9 
10 
20 
1895 
14 
11 
4 
6 
5 
11 
16 
5 
12 
8 
7 
9 
1896 
10 
6 
6 
5 
7 
10 
0 
8 
7 
10 
7 
9 
1897 
13 
2 
7 
5 
3 
4 
3 
4 
— 
5 
4 
4 
Average 
10.7 
6.7 
6.4 
5.9 
6.2 
8.7 
10.8 
10.4 
10.2 
10.7 
10.6 
10.3 
Ratio of 100 
9.9 
6.1 
6.0 
5.5 
5.8 
8.1 
10.0 
9.7 
9.4 
9.9 
9.8 
9.6 
Mean Monthly Temperature. 
From “ Monthly Weather Review,” U. S. Weather Bureau. 
Year. 
j. 
F. 
M. 
A. 
M. 
j. 
j. 
A. 
8. 
0. 
N. 
D. 
1888 
46 
53 
52 
56 
55 
61 
59 
58 
59 
59 
55 
52 
1889 
50 
54 
57 
59 
59 
60 
59 
60 
65 
62 
59 
51 
1890 
46 
49 
54 
55 
60 
59 
60 
61 
60 
62 
59 
50 
1891 
52 
51 
55 
53 
56 
60 
59 
62 
62 
60 
59 
50 
1892 
52 
52 
54 
53 
58 
57 
58 
59 
60 
60 
57 
51 
1893 
47 
50 
51 
52 
56 
56 
57 
57 
59 
58 
56 
52 
1894 
48 
48 
51 
55 
55 
56 
56 
59 
63 
60 
59 
50 
1895 
49 
54 
52 
55 
58 
59 
58 
58 
61 
59 
56 
49 
1896 
52 
55 
54 
52 
56 
57 
59 
59 
60 
59 
53 
53 
1897 
49 
51 
49 
57 
57 
59 
58 
58 
61 
58 
53 
51 
Average 
49 
52 
53 
55 
56 
58 
58 
59 
61 
60 
57 
51 SEDGWICK AND WINSLOW.—BACILLUS OF TYrHOlI) FEVEIi. 
551 
CINCINNATI. 
Monthly Typhoid Deaths. 
From Beports, Local Department of Health. 
Tear. 
j. 
F. 
M. 
A. 
M. 
j. 
j. 
A. 
s. 
o. 
N. 
D. 
1888 
41 
34 
16 
11 
6 
7 
6 
12 
17 
16 
22 
15 
1889 
11 
14 
11 
19 
7 
9 
12 
14 
14 
11 
12 
9 
1890 
18 
11 
17 
9 
14 
14 
23 
24 
20 
23 
23 
9 
1891 
10 
17 
14 
21 
14 
21 
10 
16 
7 
22 
22 
12 
1892 
17 
10 
8 
4 
4 
7 
6 
10 
12 
9 
11 
23 
1893 
10 
14 
8 
4 
14 
6 
8 
15 
14 
12 
12 
17 
1894 
18 
11 
15 
10 
10 
8 
12 
6 
10 
21 
11 
37 
1895 
22 
12 
7 
6 
5 
5 
7 
7 
8 
10 
8 
23 
1896 
34 
22 
15 
11 
11 
5 
6 
14 
9 
11 
11 
15 
1897 
9 
8 
5 
5 
10 
3 
17 
9 
9 
9 
6 
11 
Average 
19.0 
15.3 
12.6 
10.0 
9.5 
8.5 
10.7 
12.7 
12.0 
14.4 
13.8 
17.1 
Katio of 100 
12.3 
9.9 
8.2 
6.5 
6.2 
5.5 
6.9 
8.2 
7.8 
9.4 
8.9 
11.1 
Mean Monthly Temperature. 
From “ Montlily Weather Review,” U. S. Weather Bureau. 
Year. 
j. 
F. 
M. 
A. 
M. 
j. 
j. 
A. 
s. 
o. 
N. 
D. 
1888 
29 
35 
39 
55 
63 
74 
76 
73 
63 
50 
45 
36 
1889 
37 
30 
46 
54 
63 
70 
75 
72 
66 
52 
43 
48 
1890 
41 
43 
40 
56 
64 
78 
77 
73 
66 
56 
48 
36 
1891 
36 
40 
38 
56 
60 
74 
71 
72 
70 
55 
43 
42 
1892 
26 
39 
38 
53 
62 
75 
76 
75 
68 
56 
40 
32 
1893 
21 
34 
42 
54 
61 
73 
79 
75 
70 
56 
42 
36 
1894 
38 
33 
49 
54 
63 
75 
77 
77 
72 
57 
41 
37 
1895 
27 
24 
41 
55 
64 
76 
75 
77 
73 
51 
44 
37 
1896 
34 
35 
37 
62 
71 
73 
76 
75 
65 
53 
48 
38 
1897 
29 
36 
46 
52 
59 
72 
78 
74 
71 
63 
46 
36 
Average 
32 
35 
42 
55 
63 
74 
76 
74 
68 
55 
44 
38 552 
SEDGWICK AND WINSLOW. — BACILLUS OF TYPHOID FEVER. 
DISTRICT OF COLUMBIA. 
Monthly Typhoid Deaths. 
From Reports, Local Department of Health. 
Year. 
j. 
F. 
M. 
A. 
M. 
j. 
j. 
A. 
s. 
0. 
N. 
D. 
1887 
18 
32 
22 
20 
18 
15 
1888 
8 
7 
8 
7 
3 
10 
12 
23 
27 
34 
19 
7 
1889 
14 
7 
9 
5 
6 
7 
23 
18 
29 
15 
18 
29 
1890 
9 
6 
19 
11 
10 
21 
33 
26 
29 
30 
21 
17 
1891 
12 
6 
12 
5 
8 
6 
22 
21 
36 
26 
12 
1892 
13 
13 
8 
7 
8 
11 
19 
21 
30 
22 
25 
18 
1893 
6 
7 
6 
11 
11 
10 
21 
24 
28 
23 
23 
21 
1894 
10 
5 
5 
6 
5 
20 
33 
30 
26 
30 
24 
16 
1895 
3 
8 
1 
1 
1 
1 
12 
27 
56 
55 
24 
20 
1896 
9 
8 
3 
3 
4 
7 
8 
15 
25 
25 
18 
16 
1897 
13 
4 
4 
4 
6 
9 
Average 
9.7 
7.1 
7.5 
6.4 
5.9 
10.4 
18.5 
23.8 
29.3 
29.0 
21.6 
17.1 
Ratio of 100 
5.2 
3.8 
4.1 
3.5 
3.2 
5.6 
10.0 
12.9 
15.8 
15.7 
11.7 
9.2 
Mean Monthly Temperature 
From Reports, Local Department of Health. 
Year. 
j. 
F. 
M. 
A. 
M. 
j. 
j. 
A. 
s. 
0 
N. 
D. 
1887 
80.5 
73.2 
65.0 
55.4 
44.9 
37.2 
1888 
29.2 
35.7 
37.5 
52.9 
62.7 
73.0 
72.9 
73.9 
63.2 
50.5 
45.8 
35.2 
188!) 
36.8 
29.4 
42.3 
53.2 
63.8 
69.8 
74.2 
70.6 
65.6 
52.5 
46.2 
45.6 
1890 
44.2 
43.4 
41.4 
53.7 
63.8 
74.9 
75.1 
73.5 
67.7 
56.2 
47.8 
34.2 
1891 
37.3 
41.5 
38.5 
55.4 
61.3 
71.4 
72.0 
74.5 
79.2 
54.4 
43.9 
43.1 
1892 
31.7 
36.9 
37.7 
51.5 
63.8 
76 2 
75.7 
76.2 
66.2 
55.0 
43.6 
33.0 
1893 
24.0 
34.9 
41.0 
54.0 
61.6 
72.0 
77.0 
74.7 
66.0 
56.4 
43.6 
38.4 
1894 
37.7 
35.2 
48.6 
53.2 
64.8 
73.7 
78.0 
73.9 
71.4 
57.8 
43.8 
37.4 
1895 
31.6 
26.2 
41.8 
53.8 
62.6 
74.6 
72.7 
77.3 
72.4 
52.1 
46.4 
38.7 
1896 
33.3 
36.6 
38.6 
66.5 
68.8 
71.3 
76.6 
75.7 
67.7 
54.0 
50.6 
35.5 
1897 
30.9 
36.5 
46.0 
53.0 
62.5 
69.7 
Average 
34 
36 
41 
55 
64 
73 
75 
74 
68 
54 
46 
38 553 
SEDGWICK AND WINSLOW. BACILLUS OF TYPHOID FEVER. 
MOBILE. 
Monthly Typhoid Deaths. 
Obtained, in correspondence, by courtesy of Local Department of Health. 
Year. 
J. 
F. 
M. 
A. 
M. 
j. 
j. 
A. 
s. 
0. 
N. 
D. 
1889 
0 
0 
2 
2 
0 
2 
2 
3 
1 
1 
1 
2 
1890 
0 
2 
0 
1 
1 
2 
6 
2 
0 
1 
0 
1 
1891 
0 
0 
0 
0 
2 
0 
3 
0 
4 
3 
2 
0 
1892 
0 
1 
0 
0 
1 
1 
4 
3 
1 
2 
0 
1 
1893 
1 
1 
1 
1 
0 
4 
3 
1 
2 
2 
0 
0 
1894 
1 
2 
0 
0 
1 
2 
4 
1 
1 
1 
1 
1 
1895 
3 
0 
0 
0 
2 
1 
2 
3 
4 
4 
1 
2 
1896 
1 
0 
0 
0 
2 
1 
5 
1 
0 ' 
2 
3 
1 
1897 
1 
1 
0 
0 
1 
3 
4 
2 
5 
1 
2 
0 
1898 
1 
0 
2 
1 
1 
2 
6 
4 
2 
2 
1 
1 
. Average 
.8 
.7 
.5 
.5 
1.1 
1.8 
3.9 
2.0 
2.0 
1.9 
1.1 
.9 
Ratio of 100 
4.6 
4.1 
2.9 
2.9 
6.4 
10.4 
22.6 
11.6 
11.6 
11.0 
6.4 
5.2 
Mean Monthly Temperature. 
From “ Monthly Weather Keview,” U. S. Weather Bureau. 
Yew. 
j. 
F. 
M. 
A. 
M. 
j. 
j. 
A. 
s. 
o. 
N. 
D. 
1889 
51 
51 
59 
68 
70 
77 
81 
79 
77 
66 
56 
61 
1890 
62 
61 
57 
68 
73 
80 
80 
80 
77 
67 
61 
54 
1891 
49 
59 
59 
66 
72 
80 
80 
80 
77 
65 
57 
53 
1892 
47 
57 
55 
66 
72 
79 
79 
80 
75 
69 
58 
52 
1893 
46 
58 
57 
69 
74 
79 
82 
81 
78 
66 
58 
55 
1894 
55 
53 
60 
69 
74 
78 
79 
80 
78 
68 
57 
54 
1895 
49 
43 
58 
66 
72 
79 
81 
81 
81 
65 
58 
50 
1896 
49 
53 
57 
69 
76 
79 
81 
82 
77 
68 
62 
51 
1897 
48 
55 
66 
66 
71 
81 
82 
80 
78 
71 
60 
54 
1898 
55 
53 
63 
62 
. 75 
80 
81 
80 
78 
65 
56 
49 
Average 
51 
54 
59 
67 
73 
79 
81 
80 
78 
67 
58 
53 554 
SEDGWICK AND WINSLOW. — BACILLUS OF TYPHOID FEVER. 
OAKLAND. 
Monthly Typhoid Deaths. 
Obtained, in correspondence, by courtesy of Local Department of Health. 
Year. 
j. 
F. 
M. 
A. 
M. 
j. 
j. 
A. 
s. 
0. 
N. 
D. 
1889 
1 
1 
4 
2 
2 
0 
0 
1 
1 
3 
3 
1 
1890 
2 
0 
5 
1 
0 
1 
2 
1 
2 
3 
2 
3 
1891 
0 
0 
0 
2 
2 
1 
3 
4 
6 
2 
3 
3 
1892 
0 
2 
1 
2 
3 
1 
1 
2 
0 
5 
1 
2 
1893 
0 
2 
0 
0 
1 
4 
22 
4 
7 
2 
3 
1 
1894 
1 
2 
3 
1 
0 
1 
2 
2 
0 
1 
0 
1 
1895 
2 
3 
0 
3 
2 
0 
3 
1 
2 
0 
1 
1 
1896 
1 
3 
1 
0 
1 
2 
0 
0 
2 
3 
3 
2 
1897 
1 
1 
0 
0 
1 
0 
1 
0 
2 
1 
1 
1 
1898 
0 
0 
0 
0 
2 
1 
3 
2 
1 
1 
1 
1 
Average 
0.8 
1.4 
1.4 
1.1 
1.4 
1.1 
3.7 
1.7 
2.3 
2.1 
1.8 
1.6. 
Ratio of 100 
3.9 
6.9 
6.9 
5.4 
6.9 
5.4 
18.1 
8.3 
11.3 
10.3 
8.8 
7.8 
Mean Monthly Temperature. 
From “ Monthly Weather Review,” U. S. Weather Bureau. 
Yeai 
j. 
F. 
M. 
A. 
M. 
j. 
j. 
A. 
s. 
o 
N. 
D. 
1889 
48 
50 
57 
5ft 
59 
61 
60 
61 
63 
61 
57 
50 
1890 
44 
48 
54 
55 
60 
59 
62 
62 
61 
62 
57 
49 
1891 
51 
49 
53 
53 
55 
60 
61 
63 
62 
59 
57 
49 
1892 
52 
50 
53 
53 
58 
62 
64 
64 
63 
58 
53 
49 
1893 
49 
51 
54 
56 
58 
62 
62 
61 
62 
58 
54 
51 
1894 
45 
48 
52 
57 
59 
61 
59 
61 
62 
59 
56 
49 
1895 
47 
52 
51 
56 
59 
60 
63 
59 
62 
56 
54 
47 
1896 
51 
53 
55 
54 
58 
61 
64 
63 
— 
58 
51 
49 
1897 
46 
49 
49 
59 
61 
64 
63 
61 
63 
58 
51 
47 
1898 
44 
51 
51 
57 
57 
64 
62 
62 
61 
60 
53 
47 
Average 
48 
50 
53 
56 
58 
61 
62 
62 
62 
59 
54 
49 SEDGWICK AND WINSLOW.— BACILLUS OF TYPHOID FEVER. 
555 
DRESDEN. 
Monthly Typhoid Deaths. 
Year. 
j. 
F. 
M. 
A 
M. 
j. 
j. 
A 
s 
0. 
N. 
D. 
1888 
4 
2 
2 
1 
1 
0 
0 
6 
4 
1 
2 
3 
1 MHO 
4 
2 
0 
1 
3 
1 
2 
4 
1 
2 
1 
0 
1890 
1 
3 
4 
0 
1 
1 
1 
2 
1 
3 
3 
2 
1891 
3 
1 
3 
1 
2 
2 
2 
3 
3 
0 
5 
2 
1892 
0 
0 
4 
1 
0 
1 
2 
1 
1 
3 
1 
2 
1898 
1 
0 
1 
3 
1 
0 
0 
0 
1 
1 
3 
2 
1804 
0 
0 
1 
8 
3 
2 
1 
3 
5 
1 
2 
0 
189a 
1 
l 
0 
0 
2 
1 
4 
3 
1 
1 
2 
1 
1896 
0 
0 
0 
4 
2 
2 
1 
1 
0 
1 
1 
3 
1897 
0 
0 
1 
1 
1 
0 
3 
0 
2 
1 
2 
1 
Average 
1.4 
.9 
1.6 
2.0 
1.6 
1.0 
1.6 
2.3 
1.9 
1.4 
2.2 
1.6 
Ratio of 100 
7.2 
4.6 
8.2 
10.3 
8.2 
5.1 
8.2 
11.8 
9.7 
7.2 
11.3 
8.2 
From “ Veroffentlichungen des Kaiscrliclicn Gesundheitsamtes.” 
Mean Monthly Temperature. Average 18G4-1890. 
From “Amtliche Publication <les Kimigl. sachsischen meteorologischen Institutes. Das Klima des Konigreiches 
Saclisen.” Heft III, 1895. 
j. 
F. 
M. 
A. 
M. 
j. 
j. 
A. 
8. 
0. 
N. 
D. 
Centigrade 
0 
1 
3 
8 
13 
1G 
18 
17 
14 
9 
4 
0 
Fahrenheit 
32 
34 
37 
4G 
55 
Gl 
G4 
G3 
57 
48 
39 
32 556 
SEDGWICK AND WINSLOW. BACILLUS OF TYPHOID FEVER. 
MUNICH. 
Monthly Typhoid Deaths. 
From “ Veroffentliclmngen des Kaiserliclien Gesundheitsamtes.” 
Year. 
j 
F. 
M. 
A. 
M. 
j. 
j. 
A. 
8. 
0 
N. 
D. 
1888 
4 
1 
5 
3 
3 
4 
3 
0 
2 
2 
2 
2 
1889 
3 
2 
2 
2 
3 
2 
6 
1 
1 
6 
2 
1 
1890 
2 
1 
3 
2 
2 
0 
2 
4 
2 
5 
4 
1 
1891 
2 
3 
3 
3 
2 
3 
1 
1 
1 . 
3 
0 
2 
1892 
2 
1 
0 
0 
1 
3 
0 
1 
2 
0 
1 
0 
1893 
3 
3 
0 
1 
1 
20 
15 
9 
1 
3 
1 
0 
1894 
0 
0 
1 
2 
0 
1 
3 
0 
2 
0 
0 
1 
1895 
1 
2 
1 
0 
0 
1 
0 
2 
3 
1 
0 
4 
1896 
2 
2 
0 
1 
1 • 
0 
1 
3 
0 
2 
1 
1 
1897 
0 
0 
0 
2 
1 
7 
7 
5 
1 
0 
0 
0 
Average 
1.9 
1.5 
1.5 
1.6 
1.4 
4.1 
3.8 
2.6 
1.5 
2.2 
1.1 
1.2 
Ratio of 100 
7.8 
6.1 
6.1 
6.6 
5.7 
16.7 
15.6 
10.7 
6.1 
9.0 
4.5 
4.9 
Mean Monthly Temperature. 
From “ Beobachtungen der meteorologischen Stationen im KbnigreiCh Bayern.” 
Year. 
j. 
F. 
M. 
A. 
M. 
j. 
j. 
A. 
s. 
o. 
N. 
D. 
1889 
-4 
-3 
-1 
7 
15 
18 
17 
16 
11 
8 
1 
-4 
1890 
.1 
-5 
3 
7 
14 
14 
16 
17 
12 
6 
2 
-7 
1891 
-6 
-3 
3 
5 
13 
16 
17 
15 
13 
9 
1 
-7 
1892 
-2 
1 
1 
7 
13 
16 
16 
19 
14 
7 
3 
-3 
1893 
-9 
2 
4 
9 
12 
16 
18 
17 
13 
9 
1 
-3 
1894 
-5 
1 
4 
10 
11 
14 
18 
16 
11 
8 
3 
-1 
1895 
-5 
-8 
1 
8 
11 
15 
18 
17 
16 
7 
5 
0 
Average 
—4 
—2 
2 
8 
13 
16 
17 
17 
13 
8 
2 
-3 
Fahrenheit 
25 
28 
36 
46 
55 
61 
63 
63 
55 
46 
36 
27 SEDGWICK AND WINSLOW. — BACILLUS OF TYPHOID FEVER. 
557 
VIENNA. 
Monthly Typhoid Deaths. 
From “ Veroffentlichungen des Kaiserlichen Gesundheitsamtes.” 
YW. 
j. 
F. 
M 
A. 
M. 
j. 
j. 
A. 
s. 
o. 
N. 
i>. 
1888 
7 
7 
12 
8 
7 
9 
4 
4 
5 
9 
5 
26 
1889 
18 
14 
9 
9 
12 
5 
5 
5 
5 
9 
2 
8 
1890 
6 
7 
7 
7 
6 
6 
4 
6 
11 
7 
3 
7 
1894 
7 
5 
8 
5 
8 
10 
3 
12 
2 
5 
4 
5 
1895 
5 
3 
2 
2 
5 
6 
13 
12 
6 
11 
14 
7 
Average 
8.6 
7.2 
7.6 
6 2 
7.6 
7.2 
5.8 
7.8 
5.8 
8.2 
5.6 
10.6 
Ratio of 100 
9.8 
8.2 
8.6 
7.0 
8.6 
8.2 
6.6 
8.8 
6.6 
9.3 
6.3 
12.0 
Mean Monthly Temperature. 
From “ Jahrbiicher tier k. k. Central Anstalt fiir Meteorologie und Erdmagnetismus.” 
Year. 
j. 
F. 
M. 
A. 
M. 
j. 
j. 
A. 
s. 
0. 
N. 
D. 
1888 
-3 
-3 
4 
8 
15 
18 
18 
18 
15 
8 
2 
0 
1889 
—2 
—1 
1 
9 
18 
20 
19 
18 
12 
11 
3 
-4 
1890 
1 
-2 
6 
9 
16 
16 
19 
21 
14 
9 
4 
—5 
1891 
-6 
-2 
4 
7 
16 
17 
18 
17 
16 
12 
3 
1 
1892 
—1 
1 
2 
10 
14 
17 
19 
21 
16 
9 
2 
—2 
1893 
—8 
2 
6 
10 
14 
17 
19 
19 
15 
11 
3 
1 
1894 
-3 
2 
8 
15 
17 
18 
23 
20 
16 
12 
5 
1 
Average 
—3 
0 
4 
10 
16 
18 
19 
19 
15 
10 
3 
— 1 
Fahrenheit 
27 
32 
39 
50 
61 
64 
66 
66 
59 
50 
37 
30 558 
SEDGWICK AND WINSLOW. BACILLUS OF TYPHOID FEVER. 
CHICAGO. 
Monthly Typhoid Deaths. 
From Reports, Local Department of Health. 
Year. 
j. 
F. 
M. 
A. 
M. 
j. 
j 
A. 
s. 
0. 
N. 
D. 
1889 
30 
21 
15 
12 
16 
18 
29 
64 
77 
68 
68 
35 
1890 
53 
136 
103 
45 
82 
107 
86 
115 
95 
72 
67 
47 
1891 
67 
61 
71 
136 
408 
167 
200 
182 
198 
171 
150 
186 
1892 
311 
187 
76 
56 
70 
55 
211 
179 
138 
92 
67 
47 
1893 
41 
30 
41 
58 
56 
CO 
55 
76 
86 
81 
43 
43 
1894 
46 
26 
27 
30 
31 
31 
37 
52 
71 
68 
38 
34 
1895 
30 
21 
26 
30 
30 
18 
36 
59 
76 
90 
60 
42 
1896 
87 
89 
65 
33 
31 
44 
58 
64 
87 
89 
60 
44 
1897 
38 
46 
41 
19 
13 
23 
27 
42 
48 
61 
44 
35 
1898 
29 
32 
41 
94 
67 
35 
55 
45 
65 
62 
56 
55 
Average 
75 
59 
51 
51 
80 
56 
79 
88 
94 
85 
65 
57 
Ratio of 100 
8.8 
7.0 
6.0 
6.0 
9.5 
6.7 
9.4 
10.5 
11.2 
10.1 
7.7 
6.8 
Mean Monthly Temperature. 
From “ Monthly Weather Review,” IT. S. Weather Bureau. 
Year. 
j. 
F. 
M. 
A. 
M. 
j. 
j. 
A. 
s. 
0. 
N. 
D. 
1888 
15 
23 
30 
45 
53 
67 
72 
69 
60 
48 
41 
31 
1889 
29 
20 
38 
47 
57 
62 
70 
71 
63 
49 
39 
41 
1890 
31 
32 
29 
46 
53 
70 
72 
68 
60 
51 
42 
31 
1891 
30 
29 
31 
47 
53 
66 
67 
69 
69 
53 
34 
35 
1892 
19 
30 
31 
44 
52 
64 
72 
71 
64 
54 
35 
23 
1893 
12 
21 
33 
44 
52 
68 
74 
70 
.64 
53 
36 
25 
1894 
27 
23 
41 
47 
56 
71 
73 
71 
66 
52 
34 
32 
1895 
18 
17 
32 
4 6 
59 
70 
70 
72 
69 
46 
36 
30 
1896 
27 
27 
31 
53 
65 
67 
72 
73 
61 
50 
38 
33 
1897 
22 
29 
35 
46 
55 
65 
74 
69 
69 
58 
39 
25 
Average 
23 
25 
33 
46 
55 
67 
72 
70 
64 
51 
37 
32 SEDGWICK AND WINSLOW. BACILLUS OF TYPHOID FEVER. 
559 
PHILADELPHIA. 
Monthly Typhoid Deaths, r 
From Reports, Local Department of Health. 
Year. 
j. 
F. 
M. 
A. 
M. 
j. 
j. 
A. 
B. 
o. 
N. 
D. 
1888 
63 
46 
40 
37 
84 
49 
62 
169 
100 
67 
36 
32 
1889 
62 
79 
61 
41 
64 
50 
68 
83 
70 
63 
33 
66 
1890 
126 
54 
52 
52 
51 
36 
56 
62 
57 
47 
39 
34 
1891 
50 
44 
102 
141 
76 
42 
49 
42 
53 
35 
23 
26 
1892 
51 
68 
51 
37 
30 
24 
20 
40 
44 
37 
11 
27 
1893 
43 
34 
38 
35 
61 
37 
26 
47 
47 
29 
25 
35 
1894 
43 
18 
20 
25 
36 
24 
29 
50 
34 
31 
29 
31 
1895 
36 
64 
48 
40 
39 
38 
33 
36 
32 
43 
30 
30 
1896 
34 
23 
21 
40 
46 
27 
31 
38 
34 
17 
28 
63 
1897 
36 
18 
27 
41 
50 
32 
25 
49 
24 
20 
31 
48 
Average 
54 
45 
46 
49 
54 
36 
40 
62 
49 
39 
28 
39 
Ratio of 100 
10.0 
8.2 
8.4 
9.0 
10.0 
6.7 
7.4 
11.5 
9.0 
7.2 
5.2 
7.2 
Mean Monthly Temperature. 
From “ Monthly Weather Review,” U. S. Weather Bureau 
Year. 
j. 
F. 
M. 
A. 
M. 
j. 
j. 
A. 
8. 
o. 
N. 
D. 
1888 
28 
34 
35 
51 
61 
73 
72 
74 
64 
50 
46 
36 
1889 
39 
29 
42 
53 
65 
71 
75 
73 
66 
53 
47 
44 
1890 
42 
41 
39 
52 
63 
74 
75 
74 
67 
55 
46 
32 
1891 
36 
40 
38 
54 
61 
72 
72 
74 
72 
55 
44 
43 
1892 
31 
35 
36 
51 
62 
74 
77 
76 
67 
56 
44 
33 
1893 
24 
32 
39 
51 
61 
72 
77 
76 
66 
58 
44 
36 
1894 
37 
32 
47 
51 
64 
73 
78 
73 
70 
57 
42 
37 
1895 
31 
25 
38 
52 
62 
74 
73 
77 
72 
53 
47 
39 
189G 
31 
34 
36 
55 
67 
70 
78 
77 
68 
54 
50 
35 
1897 
31 
36 
43 
53 
63 
69 
76 
74 
68 
58 
46 
38 
Average 
33 
34 
39 
52 
63 
72 
75 
75 
68 
55 
46 
37 560 
SEDGWICK AND WINSLOW. BACILLUS OF TYPHOID FEVER. 
. NEWARK 
Monthly Typhoid Cases. 
From Report of Local Department of Health for 1899. 
Year. 
j. 
F. 
M. 
A. 
M. 
j. 
j. 
A. 
8. 
0. 
N. 
D. 
1890 
93 
23 
21 
17 
16 
7 
20 
10 
22 
27 
34 
57 
1891 
88 
42 
43 
18 
18 
11 
15 
167 
207 
137 
92 
38 
1892 
36 
27 
19 
11 
4 
4 
16 
32 
30 
17 
16 
17 
1893 
5 
3 
9 
6 
8 
10 
11 
26 
12 
21 
7 
7 
1894 
2 
4 
6 
9 
6 
3 
3 
10 
13 
21 
6 
5 
1895 
2 
3 
2 
1 
6 
4 
4 
31 
38 
21 
21 
15 
1896 
10 
5 
3 
2 
3 
6 
4 
14 
25 
29 
7 
8 
1897 
5 
5 
11 
7 
5 
2 
8 
7 
14 
11 
13 
15 
1898 
5 
3 
2 
3 
3 
7 
6 
38 
59 
29 
16 
8 
1899 
2 
2 
301 
67 
27 
9 
19 
28 
30 
12 
10 
8 
Average 
24.8 
11.7 
41.7 
14.1 
9.6 
6.3 
10.6 
36.3 
45..0 
32.5 
22.2 
17.8 
Ratio of 100 
9.2 
4.3 
15.4 
5.2 
3.6 
2.3 
3.9 
13.4 
16.7 
12.0 
8.2 
6.6 
Mean Monthly Temperature. 
Year. 
j. 
F. 
M. 
A. 
M. 
j. 
j. 
A. 
s. 
0. 
N. 
D. 
1890 
39 
38 
36 
49 
60 
71 
73 
72 
65 
54 
43 
30 
1891 
33 
36 
36 
51 
59 
09 
70 
72 
69 
53 
43 
41 
1892 
30 
34 
34 
49 
59 
72 
74 
73 
64 
54 
41 
30 
1893 
22 
28 
35 
47 
59 
68 
74 
73 
62 
55 
41 
34 
1894 
33 
28 
43 
49 
60 
70 
75 
71 
67 
54 
40 
35 
1895 
29 
25 
36 
48 
61 
71 
71 
74 
70 
50 
45 
37 
1896 
29 
31 
33 
53 
66 
69 
76 
75 
66 
53 
49 
32 
1897 
30 
33 
40 
50 
62 
67 
75 
72 
66 
55 
44 
35 
1898 
33 
33 
45 
48 
58 
71 
76 
76 
70 
56 
43 
32 
1899 
29 
25 
36 
49 
61 
72 
74 
72 
64 
56 
43 
34 - 
Average 
31 
31 
37 
49 
60 
70 
74 
73 
66 
54 
43 
34 
From “Monthly Weather Review,” U. S. Weather Bureau. SEDGWICK AND WINSLOW. — BACILLUS OF TYPHOID FEVLB. 
561 
PARIS. 
Monthly Typhoid Deaths. 
From “ Aimuaire statistique de la ville de Paris.’' 
Year. 
j. 
r. 
M. 
A 
M. 
j. 
j. 
A. 
8. 
o. 
N. 
D. 
1888 
146 
78 
52 
58 
54 
52 
81 
51 
70 
65 
69 
71 
1889 
69 
62 
57 
43 
53 
71 
102 
153 
120 
92 
84 
208 
1890 
74 
39 
45 
47 
51 
57 
44 
54 
76 
92 
71 
73 
1891 
65 
59 
53 
47 
36 
30 
37 
43 
40 
39 
54 
46 
1892 
50 
36 
48 
37 
48 
78 
90 
89 
97 
105 
62 
59 
1893 
48 
49 
50 
47 
29 
29 
63 
73 
72 
48 
33 
29 
1894 
25 
53 
289 
84 
34 
46 
33 
37 
21 
22 
29 
24 
189f> 
11 
9 
13 
21 
13 
25 
22 
30 
43 
34 
24 
26 
1896 
35 
17 
21 
10 
25 
9 
30 
35 
26 
17 
28 
9 
Average 
52 
40 
63 
39 
34 
40 
50 
56 
56 
51 
45 
54 
Ratio of 100 
9.0 
6.9 
10.9 
6.7 
5.9 
6.9 
8.6 
9.7 
9.7 
8.8 
7.7 
9.3 
Mean Monthly Temperature. 
From “ Annuaire statistique de la ville de Paris.” 
Year. 
j. 
F. 
M 
A. 
M. 
j. 
j. 
A. 
s. 
0. 
N. 
D. 
1888 
1 
■ 0 
4 
7 
13 
16 
16 
16 
15 
8 
8 
3 
1889 
1 
2 
4 
9 
15 
19 
18 
17 
14 
10 
6 
0 
1890 
6 
2 
6 
9 
14 
15 
16 
17 
15 
9 
6 
• > 
—o 
1891 
—1 
3 
6 
8 
12 
16 
17 
16 
15 
12 
5 
5 
1892 
2 
4 
4 
10 
15 
17 
18 
19 
15 
9 
8 
1 
1893 
-1 
6 
9 
14 
14 
18 
19 
20 
15 
11 
5 
3 
1894 
3 
5 
8 
12 
12 
16 
18 
17 
14 
10 
7 
4 
1895 
0 
-4 
5 
11 
14 
16 
18 
18 
19 
9 
9 
5 
1896 
2 
3 
9 
9 
13 
17 
19 
16 
15 
9 
3 
4 
Average 
1 
2 
5 
9 
13 
16 
17 
17 
15 
9 
6 
2 
Fahrenheit 
34 
36 
41 
48 
55 
61 
63 
63 
59 
48 
43 
36 562 
SEDGWICK AND WINSLOW. — BACILLUS OF TYPHOID FEVER. 
NEW ORLEANS. 
Monthly Typhoid Deaths. 
From Reports, Local Department of Health. 
Year. 
j. 
F. 
M. 
A. 
M. 
J. 
J. 
A. 
s. 
0. 
N. 
D. 
1886 
5 
3 
0 
0 
2 
3 
4 
3 
3 
3 
1 
3 
1887 
2 
4 
0 
1 
3 
4 
1 
4 
2 
4 
2 
7 
1890 
7 
6 
3 
2 
3 
6 
7 
4 
2 
3 
1 
6 
1891 
5 
1 
1 
1 
3 
6 
7 
6 
10 
2 
4 
13 
1892 
4 
1 
1 
2 
2 
6 
3 
10 
10 
2 
5 
5 
1893 
2 
2 
5 
1 
1 
6 
4 
1 
4 
4 
4 
5 
1896 
7 
2 
7 
8 
4 
12 
9 
14 
8 
4 
4 
11 
1897 
10 
4 
3 
7 
6 
16 
21 
18 
10 
11 
19 
16 
Average 
5.2 
2.9 
2.5 
27 
3.0 
7.4 
7.0 
7.5 
6.1 
4.1 
5.0 
8.2 
liatio of 100 
8.5 
4.7 
1 
4.0 
4.5 
4.9 
11.9 
1 1.3 
12.2 
9.9 
6.7 
8.1 
13.4 
Mean Monthly Temperature. 
From “ Monthly Weather Review,” U. S. Weather Bureau. 
Year. 
J. 
F. 
M. 
A. 
M. 
j. 
j. 
A. 
s. 
o. 
N. 
D. 
1888 
56 
59 
60 
70 
73 
77 
81 
78 
75 
68 
59 
51 
1889 
53 
53 
61 
70 
74 
78 
83 
81 
79 
70 
59 
64 
1890 
65 
64 
62 
70 
74 
81 
82 
81 
78 
69 
64 
56 
1891 
53 
63 
61 
68 
74 
81 
81 
81 
78 
68 
60 
56 
1892 
49 
61 
59 
69 
74 
79 
80 
82 
77 
71 
62 
56 
1893 
50 
61 
61 
72 
76 
80 
83 
82 
80 
69 
60 
58 
1894 
58 
55 
63 
71 
75 
78 
79 
80 
80 
71 
60 
58 
1895 
52 
45 
62 
68 
74 
80 
82 
82 
82 
69 
60 
54 
1896 
52 
56 
61 
71 
78 
80 
83 
83 
79 
70 
65 
55 
1897 
51 
58 
69 
68 
74 
82 
84 
82 
79 
74 
64 
57 
Average 
54 
57 
62 
70 
75 
80 
82 
81 
79 
70 
61 
56 SEDGWICK AND WINSLOW. — BACILLUS OF TYPHOID FEVEK. 
563 
ATLANTA. 
Monthly Typhoid Deaths. 
Obtained, in correspondence, by courtesy of Local Board of Ilealtli. 
Year. 
j. 
r 
M. 
A. 
M 
j. 
j. 
A. 
s. 
o. 
N. 
D 
1893 
1 
1 
3 
3 
4 
5 
11 
13 
7 
9 
5 
1 
1894 
0 
0 
1 
1 
3 
6 
11 
12 
7 
6 
2 
1 
1895 
0 
0 
3 
0 
1 
3 
4 
12 
14 
20 
6 
5 
1890 
3 
2 
4 
2 
3 
7 
13 
8 
10 
8 
5 
3 
1897 
1 
0 
0 
1 
0 
10 
10 
11 
9 
6 
4 
3 
1898 
4 
3 
1 
4 
4 
5 
5 
8 
8 
7 
5 
2 
A venire 
1.5 
1.0 
2.0 
1.8 
2.5 
6.0 
9.0 
10.7 
9.2 
9.3 
4.5 
2.5 
Ratio of 100 
2.5 
1.7 
3.3 
3.0 
4.2 
10.0 
15.0 
17.8 
15.3 
15.5 
7.5 
4.2 
Monthly Temperature. 
From “ Monthly Weather Review,” U. S. Weather Bureau. 
Year. 
j. 
F. 
M. 
A. 
M. 
j. 
j. 
A. 
8. 
0. 
N. 
D. 
1893 
36 
46 
51 
64 
67 
74 
81 
77 
73 
62 
51 
47 
1M94 
47 
45 
57 
62 
69 
76 
76 
76 
73 
62 
49 
46 
1895 
40 
34 
51 
60 
67 
77 
77 
77 
76 
60 
52 
44 
1896 
42 
45 
49 
66 
75 
75 
78 
80 
75 
61 
56 
44 
1897 
39 
48 
55 
60 
68 
79 
78 
76 
74 
66 
53 
45 
1898 
47 
43 
57 
56 
73 
79 
78 
77 
74 
60 
49 
44 
Average 
42 
43 
53 
61 
70 
77 
78 
77 
74 
62 
52 
45 564 
SEDGWICK AND WINSLOW. BACILLUS OF TYPHOID FEVER. 
CHARLESTON. 
Monthly Typhoid Deaths. 
From Reports, Local Department of Health. 
Year. 
j. 
F. 
M. 
A. 
M 
j. 
J. 
A. 
s. 
o. 
N. 
D. 
1888 
3 
3 
1 
0 
1 
2 
2 
7 
4 
5 
4 
4 
1889 
3 
2 
2 
4 
1 
4 
3 
5 
3 
5 
3 
5 
1890 
4 
6 
3 
2 
2 
6 
6 
8 
4 
9 
2 
4 
1891 
5 
2 
1 
0 
0 
1 
6 
3 
3 
5 
2 
0 
1892 
5 
1 
2 
1 
4 
0 
3 
3 
3 
3 
1 
1 
1898 
1 
4 
2 
0 
2 
1 
4 
2 
4 
3 
1 
0 
1894 
1 
2 
2 
2 
1 
4 
1 
2 
4 
4 
2 
0 
1895 
1 
0 
2 
1 
2 
2 
10 
3 
2 
5 
3 
2 
1896 
3 
5 
3 
3 
2 
6 
4 
5 
4 
3 
1 
5 
1897 
1 
2 
2 
4 
0 
3 
5 
5 
7 
1 
3 
7 
Average 
2.7 
2.7 
2.0 
1.7 
1.5 
2.9 
4.4 
4.3 
3.8 
4.3 
2.2 
2.8 
Ratio of 100 
7.6 
7.6 
5.7 
4.8 
4.2 
8.2 
12.5 
12.2 
10.8 
12.2 
6.2 
7.9 
Mean Monthly Temperature. 
From “ Monthly Weatlier Review,” U. R. Weather Bureau. 
Year. 
j 
F. 
M. 
A. 
M. 
j. 
j. 
A. 
8. 
0. 
N. 
D. 
1888 
51 
54 
55 
66 
72 
78 
78 
80 
74 
64 
56 
47 
1889 
52 
47 
55 
63 
74 
77 
81 
78 
76 
65 
60 
60 
1890 
59 
61 
56 
65 
73 
82 
80 
80 
76 
68 
62 
51 
1891 
50 
58 
55 
65 
70 
80 
80 
81 
76 
64 
56 
55 
1892 
48 
53 
55 
64 
72 - 
78 
80 
81 
75 
66 
57 
52 
1893 
43 
56 
56 
68 
72 
78 
83 
79 
78 
68 
58 
54 
1894 
53 
53 
61 
65 
72 
77 
79 
80 
78 
68 
57 
52 
1895 
49 
41 
56 
64 
70 
79 
81 
82 
78 
66 
58 
51 
1896 
48 
52 
55 
66 
77 
79 
82 
81 
77 
67 
63 
49 
1897 
47 
55 
61 
66 
72 
80 
82 
81 
75 
70 
62 
54 
Average 
50 
53 
57 
65 
72 
79 
81 
80 
76 
67 
59 
53 SEDGWICK AND WINSLOW.— BACILLUS OF TYPHOID FEVER. 
565 
EMPIRE OF INDIA. 
Monthly Typhoid Admissions, British Troops in Tndia. 
From Report on Sanitary Measures in India in 1806-97. Vol. XXX. 
Period. 
j 
F. 
M. 
A. 
M. 
j. 
j. 
A. 
8. 
o. 
N. 
D. 
1886-95 
518 
418 
689 
1427 
1795 
1365 
1441 
1718 
1400 
923 
745 
879 
1896 
65 
75 
202 
214 
160 
152 
175 
214 
179 
90 
92 
177 
Total 
583 
493 
891 
1641 
1955 
1517 
1616 
1932 
1579 
1013 
837 
1056 
Average 
53 
45 
81 
149 
178 
138 
147 
175 
144 
92 
76 
96 
Ratio of 100 
3.9 
3.3 
5.9 
10.9 
13.0 
10.1 
10.7 
12.8 
10.5 
6.7 
5.5 
7.0 
Monthly Range ok Temperature. 
From “ Handbuch der Klimatologie,” J. Hann. Zweite Auflage. Stuttgart, 1897 
Difference between the monthly mean and the yearly mean. Central India, Deccan, 20.8° N., 78.0° E., 390 M 
J. 
r. 
M. 
A. 
M. 
j. 
j. 
A. 
s. 
0. 
N. 
D. 
-6 
-3 
2 
6 
8 
3 
0 
0 
0 
0 
-4 
-7 
Punjab, 31.1° N., 72.3° E„ 200 M 
J. 
F. 
M. 
A. 
M. 
j. 
j. 
A. 
8. 
0. 
N. 
D. 
-12 
-10 
-3 
3 
7 
10 
9 
7 
6 
0 
—7 
-11 566 
SEDGWICK AND WINSLOW. BACILLUS OF TYPHOID FEVER. 
SANTIAGO DE CHILE. 
Typhoid cases received at Hospital S. Francisco de Borja and Hospital S. Juan de Dios, 1886-1895. 
Figures from essay, “ La Fiebre Tifoidea en Santiago,” by Pedro V. Garcia, P., “ llevista Chilena de Hijiene.” Tomo III, 
Num. 11. 
J. 
F. 
M. 
A. 
M. 
j. 
j. 
A. 
s. 
0. 
N. 
D. 
Total 
121 
121 
102 
87 
65 
49 
52 
47 
49 
60 
73 
107 
Ratio of 100 
13.0 
13.0 
11.0 
9.4 
7.0 
5.3 
5.6 
5.1 
5.3 
6.5 
7.8 
11.5 
Mean Monthly Temperature. 
From “ Observaciones meteorolrijicas hechas en el Observatorio Astronomic*) *le Santiago.” 
Year. 
J. 
F. 
M. 
A. 
M. 
J. 
j. 
A. 
s. 
o 
N. 
D. 
1882 
20.7 
18.9 
16.4 
12.6 
10.3 
8.0 
7.4 
9.5 
12.4 
15.2 
16.6 
18.4 
1883 
19.1 
18.9 
15.3 
12.8 
9.9 
7.5 
6.8 
8.9 
10.8 
13.3 
16.2 
18.9 
1884 
21.7 
18.2 
15.3 
13.3 
9.0 
7.0 
6.4 
10.3 
10.9 
13.2 
16.4 
19.0 
1885 
18.7 
18.3 
16.4 
10.3 
8.8 
7.5 
6.4 
9.4 
12.6 
13.5 
18.0 
17.4 
1886 
19.9 
18.1 
16.5 
13.4 
10.2 
6.2 
8.1 
8.7 
11.5 
14.4 
16.5 
19.4 
1887 
19.8 
18.4 
16.4 
13.1 
9.7 
8.5 
8.6 
10.5 
11.7 
13.4 
16.0 
18.1 
Average 
20 
18 
16 
13 
10 
7 
7 
9 
12 
14 
16 
18 
Fahrenheit 
68 
64 
61 
55 
50 
45 
45 
48 
54 
57 
61 
64 
BUENOS AYRES. 
Monthly Typhoid Deaths, 1876-1897. 
j 
F. 
M 
A. 
M. 
j. 
j. 
A. 
s. 
o. 
N. 
D. 
Total 
573 
534 
632 
728 
642 
487 
317 
284 
233 
262 
317 
432 
Katio of 100 
10.4 
9.8 
11.6 
13.4 
11.8 
9.0 
5.8 
5.2 
4.3 
4.8 
5.8 
7.9 
Mean Monthly Temperature, 1876-1897. 
Figures from essay, “ La Fiebre Tifoidea en Buenos Aires,” by Dr. Diego T. It. Davison, “ Anales del Departamenlo 
Naeional de Hijiene.” Ano VIII. Nuin. 13. 
j. 
F. 
M. 
A. 
M. 
j. 
j 
A. 
s. 
0. 
N. 
D. 
Centigrade 
23.5 
22.8 
21.2 
16.7 
13.2 
10.3 
10.4 
11.5 
13.3 
16.1 
19.8 
22.4 
Fahrenheit 
73 
73 
70 
63 
55 
50 
50 
53 
55 
61 
68 
72 567 
SEDGWICK AND WINSLOW. BACILLUS OF TYPHOID FEVER. 
III. INTERPRETATION OF THE STATISTICAL RESULTS. 
An examination of the curves plotted as above described shows that a very 
striking parallelism exists between the monthly variations in temperature and typhoid 
prevalence. Of the thirty communities considered, eighteen show this parallelism to 
he almost perfect; these are the Empire of Japan, the States of New York and Massa- 
chusetts, the District of Columbia, and the cities of Atlanta, Baltimore, Berlin, Boston, 
Buenos Ayres, Denver, Leipsic, London, Mobile, Montreal, New York, St. Paul, 
San Francisco, and Santiago. Three other typhoid curves — those for India, for 
Charleston, and for New Orleans — rise with the* temperature in spring, and fall with 
it in autumn, but show a temporary decrease in the disease during the time of great- 
est heat. In all these twenty-one cases the connection between the two factors 
seems too close not to indicate a vital relation. In the northern cities — Montreal, 
Boston, Denver, and St. Paul — the curve of typhoid is acute; in cities with a more 
and more equable temperature the curve of the disease is progressively flattened, the 
limit being reached in the case of San Francisco. In the northerly localities the 
maximum occurs in September and October; in the southern cities, with a milder 
winter, it comes in August (Atlanta) or July (Charleston and Mobile). In the two 
cities of the southern hemisphere the curves of both typhoid fever and temperature 
are exactly reversed. In the case of the tropical and sub-tropical regions—India, 
Charleston, and New Orleans — it appears that the rise with the temperature, after 
beginning in the usual fashion, is checked by some other factor, perhaps strong sun- 
light or extreme dryness. (See Plates I.-YIII.) 
It remains now to consider the nine cities which show more or less irregular curves, 
and to see if their abnormalities are capable of explanation. These nine cities are 
Chicago, Cincinnati, Dresden, Munich, Newark, Oakland, Paris, Philadelphia, and 
Vienna. The first thing to notice in this connection, and the one all previous students 
of seasonal variation have neglected is the necessity of discriminating between sharp 
epidemic outbreaks of the disease and the slow succession of isolated cases which 
characterize that condition known to the older sanitarians as “endemic.” The term 
endemic has been so misused and has become so associated with the idea of a 
mysterious miasm inherent in a geographical region, that it cannot be safely used in 
a more scientific sense. At the same time a distinction, vital to the epidemiologist, 
must be drawn between the infection which reaches a number of persons at once 
through a single medium as water or milk, and the slower, more complex process by 
which a disease passes from person to person through a population, the path of the 568 
SEDGWICK AND WINSLOW. BACILLUS OF TYPHOID FEVER. 
contagious material being different in each individual instance. For this sort of 
infection which spreads gradually in a community instead of striking a large number 
of persons at a single blow, the term “prosodemic,” meaning “ through” or “among” 
the people, has been suggested. 
In the examination of data bearing on the question of the seasonal prevalence of 
typhoid fever it is obviously the prosodemic disease which should be mainly considered. 
Cases of this sort furnish a large number of independent facts which may be averaged 
together fairly; while an epidemic must always be a perturbing element. Thus, for 
example, a public water supply furnishes exceptional facilities for the distribution of 
infection from its watershed to a large number of individuals. Twelve hundred cases 
of typhoid fever at Plymouth, Pa., derived from a single house on the banks of a 
reservoir have, for a study of normal seasonal variations, far less significance than 
fifty cases, in which the paths of infection are separate and independent. 
Curves of seasonal variation which are based on a small number of cases will 
always be liable to show irregularities due to single epidemics; and if our tables of 
typhoid deaths be inspected, it will at once be seen that four of the nine exceptions 
to a regular seasonal distribution are due to this cause. Thus the form of the Oak- 
land curve is distorted by the epidemic of twenty-two deaths in July, 1893, which we 
are informed by the local authorities was due to an infection of the milk supply. 
The largest number of deaths in any other month in the ten years was seven, so that 
this irregularity could not be compensated. Similarly, the Munich curve owes its 
peculiarity to the epidemic of thirty-five deaths in June and July of 1893, the largest 
number in any other month being nine. The curve for Vienna is controlled, in a 
similar way, by an epidemic in December, 1888, and January and February, 1889. In 
all these cases the curve would follow the temperature more or less normally if these 
perturbations were eliminated. Again for Dresden the total number of deaths is so 
small that eight cases in April, 1894, cause a notable distortion. That the typhoid in 
this city did follow the temperature when there was enough of it to give average 
results is shown by Fiedler’s figures for 1850-60, quoted above. 
We may thus consider that the irregularities of the Oakland, Munich, Vienna, and 
Dresden curves are explained by the fact that the number of cases considered is too 
small to eliminate the haphazard effect of epidemics. There remain to be explained 
the exceptions offered by Chicago, Cincinnati, Newark, Paris, and Philadelphia, in all 
of which cities the amount of material is amply sufficient to prevent mere chance 
irregularities. If the curves for these five cities be compared, it will at once be noted 
that they exhibit a remarkable resemblance. Besides the summer rise, each curve SEDGWICK AND WINSLOW. BACILLUS OF TYPHOID FKVEIL 
569 
exhibits two secondary maxima, one in December or January, the other between 
March and May. If our general theory be correct, there must in these localities be 
some special condition tending to produce typhoid epidemics in the early winter and 
the early spring, which modifies the normal inlluenee of the season. Fortunately, we 
know exactly what this influence is. These five cities — and of the thirty communities 
we have considered, these five only — draw their water supply from surface sources 
liable to gross pollution. The epidemics of March, 1899, at Newark ; of May, 1891, 
at Chicago; of January, 1888, and December, 1889, at Paris, as well as the lesser 
winter and spring outbreaks in other years, were unquestionably due to the public 
water supplies of those cities. We have here then a special condition influencing 
the occurrence of epidemics in cities having surface water supplies and therefore de- 
ranging the normal course of prosodcmic typhoid. The lreavy autumn rains and the 
spring Hoods consequent on the melting of the winter’s snow, carry into surface water 
supplies a larger amount of pollution than reaches them at any other time, — as is 
well shown by a comparison of the bacterial content of surface water at various sea- 
sons. We may venture to generalize by saying that winter and spring epidemics are 
characteristic of those cities whose water-supply is most subject to pollution ; they are 
absent from communities which use filtered water or water obtained from adequately 
protected watersheds. 
Finally, then, it appears that of the thirty communities we have studied, all but 
four, in which the number of cases is too small to furnish average results, give typhoid 
curves corresponding to one of three types, — the normal temperature distribution, 
the subtropical modification, and the modification due to winter and spring water- 
epidemics. These latter types of distribution are explicable as the resultant of a 
combination of the temperature factor with another. We may therefore conclude 
that wherever a sufficient number of cases has been considered a direct relation 
between typhoid fever and temperature appears to be general and invariable. 
IV. CONCLUSION OF THE AUTHORS THAT THE SEASONAL RREVALENCE OF 
TYPHOID FEVER DEPENDS MAINLY UPON SEASONAL TEMPERATURE. 
The increase of typhoid fever with a gradual rise in the mean air temperature of a 
given locality appears to he a phenomenon so widespread and significant as to indicate 
beyond reasonable doubt some relation between the two factors. Whether this rela- 
tion he direct or indirect must he determined by considerations as to the aetiology of 
the disease and as to the relation of temperature to the various vehicles mainly con- 
cerned in its transmission. 570 
SEDGWICK AND WINSLOW. BACILLUS OF TYPHOID FEVER. 
The methods by which prosodemic typhoid may spread are almost innumerable. 
The last link in the chain is, in most cases, some article of food or drink, and the food 
becomes infected, in many instances, from the fingers of a typhoid patient or of his 
unprofessional attendants. The transmission of typhoid fever on a large scale by 
water and milk has led sanitarians to minimize unduly this direct personal element in 
its mtiology. In a well-organized, thoroughly sanitary city dwelling the distinction 
between contagion and infection is an important one; but in dirty surroundings 
typhoid becomes, for all practical purposes, a contagious disease. This fact, in itself, 
throws some little light on its seasonal prevalence. A large number of persons 
who live ordinarily in cities, surrounded by many sanitary safeguards, in vacation 
time are exposed in camps and summer resorts to abundant opportunities for filth 
infection. The autumn fever, in small part at least, occurs among those who are 
attacked on such summer vacations or immediately after their return home. 
Again, several special sources of food contamination have a more potent influence at 
this season of the year. Those observers are perhaps correct who consider that ground 
waters are most dangerous when the wells are at their lowest and liable to receive 
impurities from a wide area. Professor Gualdi would explain the facts by attaching 
great significance to raw vegetables as vehicles for the transmission of typhoid fever; 
and he has traced out a more or less close connection between the consumption of 
these articles and the amount of typhoid in Rome. Most original of all is the sugges- 
tion of Bonne, who seeks to explain the autumnal maximum at Hamburg by the in- 
creased amount of bathing in the Elbe beginning with the July heat. 
Of the three great intermediaries of typhoid transmission, fingers, food, and flies, 
the last is even more significant than the others in relation to seasonal variation. 
Since the emphasis laid on this vehicle of infection by the surgeons who studied the 
conditions of the late Spanish War, our conception of its importance has grown more 
and more considerable. There can be little doubt that many of the so-called u sporadic ” 
cases of typhoid fever which are so difficult for the sanitarian to explain are condi- 
tioned by the passage of a fly from an infected vault to an unprotected table or an 
open larder. The relation of this factor to.the season is of course close and complete ; 
and a certain amount of the autumnal excess of fever is undoubtedly traceable to the 
presence of large numbers of flies and to the opportunities for their pernicious activity. 
None of the factors noted, however, nor the whole of them taken together, seem 
to us to account satisfactorily for the observed phenomena. Neither the agency of 
insects, nor the exposure of urban subjects to rural unsanitary conditions, though 
both are undoubtedly important, can be held to account for a phenomenon so con- SEDGWICK AND WINSLOW. BACILLUS OF TYPHOID FEVER. 
571 
stant, so striking, and so universal. The parallelism between the curves of typhoid 
and of temperature is too close not to suggest in the strongest manner some direct 
relation such as was postulated by Murchison, Liebermeister, and Davidson. No one 
doubts a direct correlation between the growth in a wheat-field and the changes of 
temperature during the changing seasons. The fundamental properties of protoplasm 
are so constant that there seems no reason to doubt a similar favorable effect of the 
warmth of summer, not on the crop of typhoid plants growing in human bodies, but 
on the survival seed which passes from one body to another through the environment. 
This is theoretical ; but the experiments reported in the first section of this paper 
furnish practical evidence to confirm the a priori hypothesis that it must be more 
difficult for an organism habituated to a temperature of 98 F. to persist in Nature 
when the thermometer is at 30 than when it is in the neighborhood of 80’. 
We do not wish to assert that the typhoid bacillus multiplies in the environment 
during the summer months of a temperate climate. It is the absence of the destruc- 
tive influence of cold, rather than any stimulating influence of heat, which permits the 
rise culminating in the autumnal maximum. 
In fine, the probable mechanism of the seasonal changes according to our conception 
is as follows : — 
•The bacteriology and the aetiology of typhoid fever both indicate that its causal 
agents cannot be abundant in the environment during the colder season of the year. 
The germs of the disease are carried over the winter in the bodies of a few patients 
and perhaps in vaults or other deposits of organic matter where they are protected 
from the severity of the season. The number of persons who receive infection from the 
discharge of these winter cases will depend, other things being equal, upon the length 
of time for which the bacteria cast in these discharges into the environment, remain 
alive and virulent. The length of the period during which the microbes live will 
depend largely upon the general temperature; as the season grows milder, more and 
more of each crop of germs sent at random into the outer world will survive long 
enough to gain entry to a human being and bear fruit. The process will be cumu- 
lative. Each case will cause more secondary cases; and each of the latter will have 
a still more extensive opportunity for widespread damage. In our opinion the most 
reasonable explanation of the seasonal variations of typhoid fever is a direct effect of 
temperature upon the persistence in Nature of germs which proceed from previous 
victims of the disease. PART III. 
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Medicine. English Translation, edited by Osier. Phil., London, 1901. EXPLANATION OF THE PLATES. 
Plates I.-VIII. are based upon the statistics given on pp. 540-566, as is stated on p. 539. Abscissae 
indicate months; ordinates indicate temperatures (shown by broken lines), and also percentages of 
yearly typhoid-fever mortality (solid lines) except in the curves for Newark, N. J. (Plate VI.), the 
Empire of India (Plate VII.), and Santiago de Chile (Plate V.), in which deaths, not cases, are 
indicated. 
It is important to remember that the curve of typhoid deaths in each case has been moved back 
exactly two months from its true position, and that for typhoid cases one month, as is explained on 
p. 539. PLATE. I. PLATE II. PLATE III. PLATE IV. PLATE V. PLATE VI. PLATE VII. PLATE VIII. MEMO I R S 
OF 
THE AMERICAN ACADEMY 
OF 
ARTS AND SCIENCES 
Vol. XII. 
CAMBRIDGE: 
JOHN WILSON AND SON. 
SEntbersttg 13rcs0. 
August, 1902. CONTENTS. 
PAGE 
I. Catalogue of the Magnitudes of Southern Stars from 0° to —30° 
Declination, to the Magnitude 7.0 inclusive. By Edwin F. Sawyer . 1 
II. On a Table of Standard Wave Lengths of the Spectral Lines. By 
Henry A. Rowland 101 
III. Contribution towards a Monograph of By Roland 
Thaxter 187 
IV. New Observations of the Planet Mercury. By Percival Lowell . . 431 
V. i. Experiments on the Effect of Freezing and other Low Tempera- 
tures upon the Viability of the Bacillus of Typhoid Fever, with 
Considerations regarding Ice as a Vehicle of Infectious Disease. 
ii. Statistical Studies on the Seasonal Preference of Typhoid 
Fever in various Countries and its relation to Seasonal Tempera- 
ture. By William T. Sedgwick and Charles-Edward A. Winslow 467