TRICHINA SPIRALIS: 
A LECTURE DELIVERED AT THE COLLEGE OF PHYSICIANS AND SURGEONS, FEB. 20,1809. 
JOHN C. DALTON, M.D., 
PROFESSOR OF PHYSIOLOGY AND MICROSCOPIC ANATOMY, 
[Taken from the Medical Record, April 15, 1860.] 
NEW YORK 
NAT'IIjXjI.A.IM: WOOL db 00.7 
61 Walker Street. KN GRAVED ON iSTKKL TO L-l 'iOIE ME 1) iCAL HE CO HI; 
FIG I. OLD ENCYSTED TR.CRINA FROM HUMAN MUSCI! . 
IT G. ?- RECENT ENCYSTED TRICHINA FROM HAM. 
FIR. R CYST Kl! nURt.L) BY PRESS URL AND TRI CH INA EXPELLED. 
Mdl. ENCYSTED TRICHINA EXTRACTED FROM THE CYST .AND UNWOUND. 
FRY IvADIILI fT MAL I. i Rid! 1N A WITH YOUNG FROM SMAII INTLCITNF. TRICHINA SPIRALIS 
A LECTURE DELIVERED AT THE COLLEGE OF PHYSICIANS AND SURGEONS, FEB. 20, 1869, 
JOHN C. DALTON, M.D., 
PROFESSOR OF PHYSIOLOGY AND MICROSCOPIC ANATOMY, 
[Taken from the Medical Record, April 15, 1869.] 
Gentlemen :—The subject of Trichinosis, to which our 
attention will be directed to-day, is remarkably interest- 
ing in three points of view. First of all, it is a disease of 
extreme importance with regard to its possible frequen- 
cy, the fatality which it sometimes manifests, and the 
ease with which, at any time, it may show itself in a com- 
munity where it has been previously unknown; at the 
same time it is a preventable disease ; and in the third 
place, it is especially interesting as an instance of a mal- 
ady which has been discovered, so to speak, suddenly, 
within a comparatively short period, although undoubt- 
edly it has existed unrecognized from time immemorial. 
Trichinosis, as you are all now aware, is a disease pro- 
duced by the infection of the muscular system by a 
minute parasite, which has received the name of tri- 
china spiralis. The existence of trichina spiralis in the 
muscles of the human subject has been known for over 
thirty-five years. As early as 1832, little bodies were 
discovered in human muscle, which upon examination 
were found to consist of ovoid sacs, and a few years later 
it was found that each one of these sacs contained a mi- 
nute round worm coiled spirally upon itself. This dis- 
covery was first made in the muscles of a hospital pa- 
tient. In that case it was found that the trichinas were 
exceedingly numerous and scattered throughout the 
body, in the substance of the voluntary muscles. Since 
that time they have been noticed, in many instances, in 
persons who have died from accidental causes, from 
pneumonia,from phthisis, and various other affections: 
from diseases, in a word, which would appear to be 
entirely disconnected with the existence of the para- 
sites ; so that notwithstanding the great abundance of 
. the parasites, medical men were forced to the conclusion 
that they exerted no deleterious influence whatever 
upon the subjects inhabited by them. 
I have here a specimen, which I took myself from 
the human subject, some ten years ago. It is the rec- 
tus femoris muscle, and, like the other voluntary muscles 
in this case, it is full of these parasites. You will see 
here the regular appearance of the trichinae as they are j 
usually seen, and as they were exclusively known pre- 
vious to about the year 1855. Look at this muscle very 
carefully; you will find, just visible to the naked eye, 
minute ovoid bodies situated between the muscular 
fibres, having an opaque envelope and a transparent, 
but apparently dark-colored, centre. On dissecting out 
these bodies with needles, it is found, as I have said, 
that they consist of an ovoid sac, and inside this sac the 
worm lies, spirally coiled up. This is the old encyst- 
ed trichina, such as you see in this drawing. (Vide 
Plate, Fig. 1.) 
Between the fibres of the muscle, and lying parallel 
with them, is the ovoid sac, somewhat pointed and yet 
slightly rounded at its two ends, and swollen in the 
middle, where the worm is coiled up. Now the tri- 
china is coiled in such a manner inside the sac, as to make 
about two turns and a half upon itself. One extremity 
of the worm is blunt and rounded, the other is more 
| pointed, and the two lie so near each other that half a 
I turn more would bring them together. These bodies, 
' I although so minute, are yet visible to the naked eye on 
close examination in such specimens as this; because, 
as you readily find under the microscope, they are part- 
ly solidified by a calcareous deposit in the cavity of the 
sac. This deposit! is of a gritty and almost crystalline 
texture, brittle, breaking upon firm pressure, and is 
composed, probably, of phosphate of lime, slowly depos- 
ited. so as to give to the extremities of the sac an opaque 
appearance and a very firm consistency. 
This is the condition in which the trichina presented 
itselfin all specimens brought to the observation of med- 
ical men, for some twenty-five years after its first 
discovery. They were cases of old, encysted trichinae. 
All that was known about them was that they were 
encysted, that they did not exhibit any distinct sexual 
apparatus, and that they did not appear to produce any 
distinct symptoms by their presence in the human 
organism. 
But between the years 1850 and 1860, certain ex- 
| perimenters in Germany undertook to examine the nat- 
I ural history of this parasite more closely. They did 
I so by administering portions of muscle infected with it 
to the lower animals; and they found—especially Leuck- 
art, who was the most successful in these investigations 
—that the worms, apparently so insignificant in size, and 
! so incomplete in development so long as retained in the 
| muscular system, become further developed when intro- 
i duced into the intestine of another animal. After a 
j short time the sexual apparatus appears, copulation 
takes place, the female produces living young, and these 
young penetrate finally into the muscular tissue of the 
second animal, and there domicile themselves for an in- 
’ definite time. In this way somewhat more definite 
ideas were acquired with regard to the natural history of 
the worm, as found in the inferior animals. By a con- 
tinuation of these experiments, it was found that this 
infection of the muscular system with trichina may 
show itself in the pig, the cat, the rat, the mouse, the 
rabbit, and, I believe, one or two other species of the 
inferior animals. 
So far, nothing more had been learned with regard to 
trichinosis as constituting a disease in the human 
subject. The new era in this respect opened with the 
year 1860. At that time an epidemic of trichinosis oc- 
curred in Germany. The members of a family living 
in Dresden were taken sick with symptoms similar 
to those of acute rheumatism, mingled with those of 
typhoid fever. One of them, a servant-girl, died, and 
on examination it was found that her muscles were filled 
with trichinae. The attending physician and Professor 
Virchow tried the experiment of administering the trichi- 
nous muscles to a rabbit, and found that the rabbit be- 
came infected with the parasite, and died in about four 
weeks’ time. The infected tissues of this rabbit were 
administered to a second, which became infected in the 
same manner, and died, like the first, in about four 2 
TRICHINA SPIRALIS. 
weeks. Finally, a third rabbit wasted with the flesh of 
the second, with a similar result. These experiments 
show that the disease, as it exists in the human sub- 
ject, may be transmitted to the lower animals; that it 
may be transmitted indefinitely from one animal to 
another, the parasites passing alternately from the intes- 
tines to the muscular system, and again from the mus- 
cular system to the intestines. These are the general 
outlines of the origin and course of the disease known 
as trichinosis. 
Now let us see what are the details of the anatomi- 
cal structure and physiological development of the 
worm itself. 
I have said that, as you examine the trichinae in 
those cases where they have existed in the muscles for 
an indefinite period, where they have become encysted, 
and the cavity of the cyst has been invaded by cal- 
careous deposit, it is not easy to make out their ana- 
tomical structure. But in cases where the disease is 
recent, and particularly where it can be traced to the 
recent use of trichinous flesh as food, the anatomy of 
the worm can be made out with more distinctness. 
Such a case happened in this city about five years ago. 
Some sailors, on board ship, were taken sick while in 
port with symptoms resembling those noticed in the 
Dresden family, similar to those of typhoid fever and 
acute rheumatism combined. It was found that the 
disease originated, in their cases, from eating raw pork 
or bacon. About the same time other cases of the dis- 
ease became developed in persons living permanently 
in the city; and it was found in these cases that the 
difficulty could be traced to the use of ham imperfectly 
cooked. 
A portion of this ham came into my possession, and 
in examining it I found not only that the meat was 
trichinous, but also that the parasites were in a de- 
cidedly different condition from that which they ex- 
hibit in cases of long standing. The first peculiarity 
was that the cysts in which the worms were contained, 
instead of having definite and rounded ends, gradually 
tapered off into long and slender prolongations, the ex- 
tremities of which could not be reached, being en- 
tangled in an intricate manner with the muscular fibres. 
In these drawings you see represented the cysts con- 
taining the trichinae, as found in the ham. (Fig. 2.) In 
this case the cyst is evidently a hollow, fusiform tube, con- 
sisting of a transparent and structureless, but well-devel- 
oped, membrane, containing the worm coiled up, as you 
see. From the two extremities of this fusiform cyst run 
off the prolongations. It is very important to ascertain 
exactly the structure of these prolongations. It is evi- 
dent that they are tubular, and that their cavity is 
nearly continuous with that of the sac containing the 
worm. Not quite so, however, for it can be seen that 
a membranous partition runs across where the pro- 
longations begin, so that the worm is enclosed in a dis- 
tinct cavity; and that the prolongations are tubes of 
much smaller calibre, but were apparently at some pre- 
vious time connected with the central cavity. Now 
this central cavity contains a transparent fluid; the 
worm is, therefore, lying free in the interior of the sac, 
not connected with its membranous walls ; this can be 
demonstrated by breaking open the sac by a slight press- 
ure between the glass plates. It ruptures, and dis- 
charges the worm, which escapes in such a manner as 
to show that it lay before perfectly free within the 
cavity of the sac. (Fig. 3.) The worm still remains coil- 
ed up, after its escape, and you will usually find much diffi- 
culty in uncoiling it sufficiently to examine its structure. 
No operation in microscopic anatomy requires more pa- 
tience than this; for its firm folds must be unwound with- 
out rupturing any of its parts, in such a manner as to give 
you a fair view from one extremity to the other. (Fig. 4) 
This done, the trichina, at this stage of development, is 
found to be a worm one twenty-eighth of an inch in 
length ; its anterior extremity or head is tapering and 
pointed; the body very gradually enlarges as you pass 
from the anterior extremity towards the middle, and 
about the middle acquires its greatest diameter, which 
it retains throughout the rest of its extent, terminating 
posteriorly in a round, blunted extremity. The alimen- 
tary canal runs longitudinally throughout the whole 
length of the worm, there being a mouth at the ante- 
rior or pointed extremity, and an anus at the posterior 
or rounded end. About the junction of the middle 
with the posterior third of the parasite, the calibre of 
the alimentary canal suddenly contracts, then enlarges 
again, and afterward remains reduced to about one-third 
its original size. The only other organ visible at this 
time is one which occupies, together with the alimen- 
tary canal, the posterior third of the worm; an organ 
apparently tubular in character, rounded at either end, 
and filled with rather large and tolerably well-defined 
cellular bodies. This evidently is the sexual apparatus, 
such as it exists at this time. 
The characters which I have given are sufficient to 
define the encysted trichina as taken from the muscles. 
Suppose now a portion of muscular flesh, filled with tri- 
chinae in this condition, be taken as food by the human 
subject or administered to one of the lower animals. 
On arriving in the small intestine, the worms are found to 
be perfectly free, for the muscular tissues in which they 
were imbedded, as well as the cysts in which they 
were contained, are digested in the stomach, so that 
within twenty-four or forty-eight hours you find an 
abundance of free trichinae in the cavity of the duode- 
num. At once they begin to increase in size, so much 
so that very soon, usually by the fourth or fifth day, they 
have become three or four times as large as before. They 
have now arrived at the adult condition. At the same 
time the sexual apparatus, before so incomplete, has 
become perfect, and the copulation of the sexes takes 
place. I have myself, on several occasions, found in 
the intestine of the rabbit the two sexes in copulation, 
the male fastened upon the female at the orifice of the 
generative apparatus. The eggs having been impreg- 
nated, as the animal is viviparous, the female soon 
becomes full of the young brood. 
In this drawing you see these parts as I have just de- 
scribed them. (Fig. 5.) Instead of the intestine now tak- 
ing up the whole of the anterior two-thirds of the body, 
and a great part of the posterior third, you find that the 
sexual apparatus is by far the most prominent organ in 
the interior of the body of the female; and as soon as 
the young have arrived at the period of development 
here represented, they begin to move forward to 
the terminal duct of the generative apparatus. This 
can now be seen very clearly, running from the ovary 
forward to a point quite near the anterior extremity of 
the worm. The young are very numerous. I do not 
know that it has been calculated how many a single fe- 
male is capable of producing, butthey are probably very 
numerous. The young, discharged in this w-ay into the 
cavity of the small intestine, begin to penetrate through 
its mucous membrane, by a boring process, passing un- 
doubtedly through the entire thickness of the intestinal 
walls. This causes a great deal of irritation, which 
is the first symptom of trichinosis. It is usually suffi- 
cient to produce a considerable degree of pain, and not 
unfrequently a smart attack of diarrhoea. 
After passing through the walls of the intestine, the 
worms disperse in every direction, and from that time 
you begin to find them in the muscular tissue through- 
out the body. There they domicile themselves, and, TRICHINA SPIRALIS. 
3 
within a fortnight after the symptoms have begun to 
manifest themselves in the human subject, you will find 
them almost everywhere, scattered throughout the vol- 
untary muscles. They are still very small, having 
increased but little in size during their transit, so that 
when they first arrive in the muscular tissue they are 
not more than about l-140th or l-120th of an inch in 
length. They soon, however, become encysted, and 
then increase very considerably in size. At first, 
however, they are not enclosed in distinct sacs, but 
are found contained in the interior of long tubes. 
We have already seen that, although the encysted 
trichina is contained in a sac or cavity of its own, this 
sac is often connected with prolongations running out 
from each extremity ; and in the human muscle, within 
the first fortnight of infection, the young worms are 
found contained in swollen tubes. This is the con- 
dition of the worm as it was found in the muscles 
of the human subject on the thirteenth day of illness 
in a case which I had the opportunity of examining. 
The worm, you see, is not free, but is contained in 
the interior of a tube, swollen or fusiform at the point 
where the worm lies partly coiled up. The worm is not 
■stationary at this time, but by gentle pressure can be 
made to move from one end to the other of the swol- 
len portion of the tube. By about the end of the 
first fortnight its coils assume a considerable degree of 
regularity, and the worm then reaches that condition 
which has given it its name of trichina spiralis. 
We have now described the worm as domiciled in 
the muscular tissue. The next question is, How did it 
get there, and what is the nature of this tube which it 
now inhabits, and which is hereafter to become its 
cyst ? These are points with regard to which some doubt 
still remains. Most of the German observers are agreed 
that this tube is a muscular fibre; they believe the 
worm passes from the intestine to the remotest regions 
of the body by boring its way through the intermus- 
cular cellular substance ; and that if examined on its 
first arrival there, it is perfectly free; that it then pen- 
etrates the substance of the muscular fibre, producing 
atrophy and degeneration of its substance, until the 
fibre becomes converted into the tube with prolonga- 
tions which I have described. On the other hand, it is 
possible that the worm, instead of working its way 
through the intermuscular cellular tissue, may also be 
transported by the circulation; for if it can bore 
through the walls of the intestine, it can, of course, also 
penetrate the blood-vessels, and it might thus finally 
reach the left side of the heart, and be sent with the 
current of the circulation to every part of the body. 
However, it is certain that the young trichinae arrive 
at the muscular tissue, either by working their way 
through the intervening cellular tissue or by distribu- 
tion by the blood-vessels. They very soon present 
themselves in the interior of these swollen tubes, which 
may be either capillary vessels that have become 
plugged, by coagulation of the blood, or by deposit of 
exuded material excited by the presence of the worm; 
or may be muscular fibres that have undergone degen- 
eration and atrophy from its presence. Soon the tube 
containing the parasite suffers a further alteration. 
An exudation takes place around the worm, so that 
that part of the tube containing it is shut off from the 
rest; and the remainder of the tube becomes atrophied 
into slender, tapering prolongations. After some years 
these also entirely disappear, and you see only an 
ovoid sac without prolongations; and finally you may 
have the cavity of the cyst invaded by a calcareous de- 
posit, as I have already described—the last peculiarity 
of the degenerated cyst. 
Now all these changes in the history of the trichina 
have been seen in the human subject; the develop- 
ment of the young in the body of the female; their 
discharge from the mother’s body into the intestine; 
their penetration of the ■walls of the intestine and dis- 
persion to the muscular tissue throughout the body; 
their domiciliation in the interior of the tubular cavities, 
and the change of the tubular cavities into ovoid cysts; 
the calcification of these cysts; and the quiescent and 
dormant condition of the worm as the result. 
Now to what symptoms does this accident give rise ? 
As I have already said, within the first ten days there 
is irritation of the intestines. In some instances this 
irritation is very great; and the greater it is, the more 
favorable the prognosis, as a general rule. After eating 
trichinous flesh, the patient generally begins to suffer 
within the first week, sometimes within two days. 
Now, if the irritation of the intestine be extreme, so 
that frequent and abundant evacuations are produced, 
the chances are very great that all, or nearly all, of 
the parasites will be discharged from the intestine. 
If so, the patient is safe. But if the irritation be not 
very marked, time is allowed for the young trichinae 
to penetrate the intestinal walls, and enter the muscular 
tissue—from the end of the first to the end of the second 
week. This is the most dangerous period, the second 
stage of the disease. There is general pain and sore- 
ness, and cedematous swelling throughout the muscular 
system. At the same time typhoid symptoms mani- 
fest themselves; the patient is debilitated, his pulse 
rapid, skin hot, tongue and lips dry, and his general 
appearance closely resembles that of a patient with 
typhoid fever. 
The passage of the worms into the muscular tissue, 
and the changes taking place there, are very apt to pro- 
duce symptoms which result in the patient’s death at or 
before the end of the fourth week. By that time the 
worms have become completely encysted, and after this 
the symptoms of irritation begin to disappear. The 
muscular system becomes habituated, as it were, to the 
presence of the parasite ; and after a while the symp- 
toms all subside; the patient can move his limbs as be- 
fore, and then considers himself as entirely recovered. 
How long may the worms remain in this quiescent 
condition in the interior of the muscular system ? In 
1863 Prof. Langenbeck of Berlin was operating upon a 
patient for a tumor of the neck, situated upon the sur- 
face of the sterno-mastoid muscle : in dissecting it off, 
the fibres of this muscle were disclosed, and it was no- 
ticed that their surface was covered with minute white 
specks. These attracted so much attention that a por- 
tion was excised and submitted to the microscope, when 
the specks were found to be encysted trichinae. After 
the patient’s recovery, minute inquiries were made to 
ascertain at what time he had become infected. The 
result was that no such attack could be traced to a pe- 
riod less remote than eighteen years before. At that 
time, viz,, in 1845, the patient, -with several associates, 
was serving upon a committee of inspection of the public 
schools. After the inspection in a certain district, the 
committee partook at the village inn of a lunch, consist- 
ing, in part, of ham. Very soon after, all the members 
of the committee were taken sick with symptoms simi- 
lar to those which we now know to be attributable 
to trichinosis. Two of them died, and the signs of 
poisoning were so marked that the innkeeper was 
arrested and held under this charge for a consider- 
able time. Although finally the circumstances were 
not found sufficient for his conviction of the crime, 
yet they were considered as so much against him, 
and the prejudices of the community were so ex- 
cited in consequence, that he was obliged at last to leave 
the place. On going over all the history of the case, so 4 
TRICHINA SPIRALIS. 
far as it could be ascertained at that time, it left an un- 
doubted impression on the minds of the medical men 
who made the investigation, that at the time before- 
mentioned, viz,, in 1845, the members of the commit- 
tee were infected with trichinae from the ham used for 
their lunch ; that two of them had died in consequence ; 
and that Prof. Langenbeck’s patient had recovered, and 
the worms remained encysted for eighteen years after- 
ward. How much longer they may thus remain Ido not 
know, but I see no reason why they should not last 
for the remainder of the patient’s life. They produce in 
this condition no interference with the health, and hard- 
ly seem to interfere even with the vigor of the mus- 
cles. 
a personal examination of every piece of pork, ham,, 
bacon, or sausage used as food, to see that every part 
of it has been to a thorough cooking pro- 
cess. 
One other point still I should like to speak of. We- 
have seen that the disease shows itself occasionally in 
the human subject, but very frequently in the pig- 
Now, how is it, under these circumstances, that the 
continuance of the species of trichina spiralis i& 
provided for by nature ? We have here an animal 
that arrives at maturity in the intestine of the human 
subject. In that situation the female bears living 
young in consequence of the individual having eaten 
pork filled with the encysted and quiescent trichinae- 
So long as these remain encysted and quiescent in the 
pig’s muscles they remain practically undeveloped and 
practically sexless. This flesh is eaten by the human 
subject. In the intestines of the human subject the 
worms are set free, the females are impregnated and 
bear young, and these scatter themselves throughout 
the body. Now, when these young have, in their turn- 
in the human subject arrived at the period of 
quiescence, how are they ever to get back to the 
intestine of a living animal, and so become capable of 
continuing their species ? 
I presume that the mode by which the race is contin- 
ued is this : Suppose we start with the pig infected with 
quiescent and sexless trichina. This pig is butchered- 
You know that butchering establishments are the 
abundant resort of rats, which feed upon the refuse 
scraps of meat, and of course these after a time become 
infected with trichina. The worms are developed in 
the intestine of the rat, and produce living young. 
These not only infect the muscular system of the rat, 
but they are also discharged with the faeces. These 
feces become mingled with the food of the pig,—an 
animal, as we know, not very fastidious with regard 
to his food, and subject to several para- 
sitic diseases,—and thus the round of development of 
the trichina is completed. Again, its perpetuation is 
provided for by a similar round between the cat and 
the mouse. The mouse becomes infected by feeding 
upon refuse meat, and the cat by devouring the mouse 
or rat. We have therefore the natural history of the 
animal, embracing in each case two different phases, in 
one of which it undergoes an active development, in 
the interior of the intestine, while in the other it 
assumes the quiescent form, becoming encysted in the 
substance of the muscular system. 
There are other points of considerable interest with 
regard to the rapidity with which the human subject 
may be infected, the great number of persons who 
may become infected by eating the product of a single 
slaughtered animal, and the degree of fatality attending 
the disease. Enough, however, is known to convince 
us that the affection is a very frequent one, and liable 
to be exceedingly fatal, or if not fatal, to produce pro- 
longed and exhausting disease. 
Much would be effected if all pork offered for sale 
in the market could be subjected to inspection; and this 
has been done in some parts of Germany ; pork being 
liable to infection not only with trichina, but also with 
cysticercus, producing tape-worm in the human subject- 
Such inspection would undoubtedly prove very useful. 
Still it would not afford complete protection, unless 
carried out with an amount of detail which would in 
all probability prove practically unattainable. The 
only absolute protection, therefore, must be that exer- 
cised by the individual for himself. He must see that 
he never uses for food any kind or preparation of pork 
in any form not so thoroughly cooked as to destroy 
every possible vestige of parasitic life. 
This was the condition in which the trichinae were 
nearly always found, prior to the year 1850, and from 
this fact it was supposed that the trichina was a harmless 
parasite. Such are the chief circumstances connected 
with the physiological history of the worm. 
There still remains one question of a very important 
nature,—How great is the liability of the community 
at the present time to be infected, and what measures 
can be taken to prevent it? 
The pig seems to be the animal naturally the most li- 
able to trichinosis. He is certainly more liable to this 
disease than any other animal used for food, neither 
the sheep nor the ox being subject to it. It has been 
found in this country, by investigations in Chicago in 
1866, that of all the pigs brought to market in that 
city, one in fifty is infected with trichina. This shows 
that we are all in danger of becoming infected by the 
use of pork, unless measures be taken, in preparing the 
meat, to destroy the vitality of the worms. Smoking 
and salting will not do this effectually. Only thorough 
cooking is to be relied on as a safeguard. It is remark- 
able that most, if not all of the cases of trichinosis in 
this country, thus far have occurred among the Her- 
mans. This is because they have the habit, not 
otherwise common here, of eating ham, sausages, and 
even sometimes fresh pork, nearly or quite in the un- 
cooked state. To kill the worms the ham must not 
only be salted and smoked, it must be cooked, and 
cooked thoroughly. Now, if you bear in mind that 
one pig in fifty is infected with trichina, you will per- 
haps think many times before putting between your 
lips a piece of pork, or ham, or sausage in the raw state; 
you will be certain that it is cooked; and not only that, 
bat thoroughly cooked. One of the worst cases of trichi- 
nosis that has come under my observation was caused 
by eating pork chops which were rare or slightly un- 
derdone. Now, these chops were probably well 
enough cooked on the outside; but on the inside 
they were red and juicy, and the danger was pre- 
cisely the same as if the patient had taken the meat 
entirely raw. In order to destroy the vitality of the 
trichina the meat should be subjected to a temperature 
of 212° F. Now, if you boil a ham for half an hour, 
or even an hour, you do not necessarily subject 
all parts of it to this temperature. In the central 
parts of the ham the temperature will not rise to 
that point unless the boiling has been long continued. 
I speak of this particularly, as it is a very important 
matter. A temperature of less than 160° F. does not 
destroy the trichina. As shown by direct experiment, 
therefore, a piece of trichinous meat, any part of which 
has not been raised to or above this point, is just as 
dangerous as if it were taken in the raw state. 
These are the chief points of importance in regard to 
the trichina and trichinosis. The disease is fatal 
enough, frequent enough, and revolting enough to 
induce us to take all possible measures to prevent it, 
and I do not think anything is sufficient for this but