SOME CONSIDERATIONS CONCERNING 
ANTISEPTIC SURGERY. 
BY WILLIAM h. WELCH, M. D., 
OF BALTIMORE. 
Reprinted from the Maryland Medical Journal of November 14, 1891, SOME CONSIDERATIONS CONCERNING ANTISEPTIC SURGERY.* 
BY WILLIAM H. WELCH, M. D., 
Professor of Pathology, Johns Hopkins University. 
Reprinted from the Maryland Medical Journal, November 14th, 1891. 
The greatest achievement of modern surgery is not so much the triumph of 
abdominal or of cerebral surgery, or of any particular class of operations, as it is 
the method which has brought into che surgeon's domain every organ of the 
human body. The victories of this method are manifested not less in the aseptic 
healing of the wound resulting from the removal of a simple wen, than in the re- 
covery without suppuration and fever after the extirpation of a cerebral tumor, 
or of a large abdominal tumor. 
Modern surgery begins with the introduction of antiseptic methods of wound 
treatment, and it is the imperishable merit of Lister to have ushered in this era 
by his recognition of the great truth that the infection of wounds depends upon 
the presence of bacteria and by his adoption of measures of treatment based upon 
this truth. Upon the establishment of these fundamental principles his fame 
will rest, even if every detail in his original method of treatment be replaced by 
means found better suited to the purpose. 
No apology is needed if a pathologist ventures to speak to you about a subject 
with such practical bearings as surgical antisepsis, when it is recalled that an- 
tiseptic and aseptic methods of wound treatment rest upon bacteriological work 
no less than upon clinical experience. In the development of these methods the 
surgeon and the bacteriologist have worked hand in hand. The harmony and 
♦An aldress'before the Clinical Society of Maryland, on October 16th, 1891. The address was delivered 
extemporaneously and this paper is from the stenographer’s report, revised by the author. co-operation between tbe worker in the laboratory and the practical physician and 
surgeon have never been so great as at the present time. On the one hand, the 
experimenter applies himself to problems of immediate interest to the practitioner 
and seeks the aid of clinical observation as never hefore, and the practitioner is 
eager to learn and to apply the established results of experiment. That this 
combined work is calculated to advance scientific and practical medicine in the 
surest way cannot be doubted. 
Lister’s original antiseptic methods, which were introduced about the middle 
of the sixth decade of this century, were founded mainly upon the views which 
prevailed at that time as to the relation of bacteria to the processes of putrefac- 
tion and fermentation. One chief source of the bacteria which infect wounds was 
regarded as the air; and by the use of carbolic acid spray he hoped to disinfect 
the air over the field of operation. Lister also employed carbolic acid as the 
agent for disinfecting the wound, hands, instruments and all that might come 
in contact with the wound. The dressings applied to the wound were perme- 
ated with the disinfectant and were expensive and somewhat complicated. The 
method necessitated extensive use of drainage tubes and frequent change of 
dressings. 
Theresults of this method marked a great advance in surgery, the contrast 
between the new and the old method being more evident in Germany than in 
Great Britain, because in the former the hospitals were, in general, older, less 
cleanly and in a less sanitary condition. Good as were the results of the new 
method, they were still so far from perfect that efforts continued to be made to 
improve the method. 
It is evidence of the value and fructifying influence of the new ideas intro- 
duced by Lister that they have proven capable of wide development; that they 
have stimulated workers in science and in practical medicine to efforts whieh 
have extended our knowledge far beyond the mark of a quarter of a century ago; 
and that they have occasioned unprecedented activity and progress in surgery 
during this period. Permit me to direct your attention to some of these advan- 
ces in the general principles of antiseptic surgery, looking at the subject rather 
from the point of view of the bacteriologist than from that of the practical sur- 
geon. In the limits of a paper of this kind it is possible to select for considera- 
tion only a few points, leaving many of great importance untouched. 
The most fundamental advance relates to the extension of our knowledge con- 
cerning the nature and habits of the micro-organisms which cause traumatic in- 
fections. As has already been said, Lister’s early work was based upon analo- 
gies drawn from the relation of bacteria to the processes of fermentation and 
putrefaction. Nothing or almost nothing was known as to the bacteria actually 
concerned in suppuration and other wound infections. The observations of 
Klebs, Recklinghausen and others at this period concerning the presence of mi- 
crococci in pyaemia and other suppurative conditions gave little information as 
to the character and behavior of these organisms. 
The new era in bacteriology was introduced by the publication of Robert 
Koch’s Untersuchungen iiber die Aetiologie der Wundinfeciionskrankheiten, in 1878. 
The kind of evidence necessary to prove the causation of a disease by a speci- 
fic micro-organism was here clearly set forth and was brilliantly illustrated by Ins 
study of a number of new infectious diseases, chiefly experimental septicaimias, 
produced in mice and rabbits by the inoculation of foul substances. Three 
years later, Koch gave to the world the details of his method of cultivating bac- 
teria upon solid transparent media, without which most of the great discoveries 
in bacteriology during the last decade could not have been made. 3 
Although Koch’s epoch-making publication was entitled Investigations Con- 
cerning the Etiology of Traumatic Infections, this did not relate to the bacteria 
which cause wound infectious in human beings; and it was hardly less mis- 
leading when inferences were drawn as to the nature and mode of causation of 
suppurative and other traumatic infections of human beings from supposed 
analogies with Koch’s experimental septicaemias, than from those with fermenta- 
tion ana putrefaction. 
The first thorough study by modern bacteriological methods of the bacteria 
causing suppuration in human beings was made by Ogston, Rosenbach and Pas- 
set, between the years 1880 and 1885. To this period belongs also the study 
anil first cultivation of the erysipelas coccus by Fehleieen. Ogsfon confined his 
attention to the microscopical observation, by the improved optical aids, of the 
staphylococci and streptococci of suppuration. The other investigators isolated 
in pure culture and studied the different species of bacteria found in abscesses. 
These fundamental researches made us familiar with the ordinary pyogenic staphy- 
lococci and streptococci. Kow, for the first time, the causation of the most com- 
mon, and, therefore, the most important, of all traumatic iufections, namely, the 
suppurative, could be satisfactorily studied. The commonest enemies of the 
surgeon were known, their distribution in nature, the ways in which they may 
gain entrance to wounds, their habits and behavior both inside and outside of 
the body, were open to direct observation and experiment. It could not be 
doubted that this increased knowledge would lead to more efficient means of 
combatting the enemy, and this has proven true. 
Although we have learned that many other species of micro-organisms than, 
those originally described by Ogston, Rosenbach and Passet may be concerned 
in traumatic infections of human beings, nevertheless the pyogenic cocci are by 
far the most common and important, and these are the ones which have been 
most thoroughly studied. It soon became evident that the study of infection 
with the pyogenic cocci presents many peculiar and complicated problems; and 
we owe especially to Grawitz and his pupils the demonstration that under ordi- 
nary conditions, the healthy tissues in many situations are capable of disposing 
of a large number of these cocci without manifest injury, and also the recogni- 
tion of several abnormal conditions which deprive the tissues of this power. 
It is becoming every day clearer that the most valuable friend which the sur- 
geon has in hisefforts to secure aseptic healing of his wounds is the capacity of 
the fluids and cells of the animal body to overcome invading micro-organisms. 
The indication is no less urgent than ever before to keep bacteria out of wounds 
in every way possible, but it seems plain that hitherto the efforts of the antisep- 
tic surgeon have been directed tooexclusively toward this indication and toward 
the attempted destruction of bacteria which may have accidentally entered the 
wound, and not enough toward preserving, as far as possible, the germicidal power 
of the tissues and fluids. 
Among the influences which have been found favorable to the growth in wound* 
of bacteria, which otherwise might be disposed of by the tissues and animal 
fluids without harm, are the presence of foreign bodies, such as drainage tubes 
and coarse ligatures, the necrosis and degeneration of tissue caused by the eon- 
tact of strong chemical disinfectants with the wounded tissues, the strangulation 
of masses of tissue with ligatures, the strangulation, tension and interference 
with the circulation often caused by deep coaptation sutures, and interference 
with the circulation and vitality of tissues which may result from too forcible 
pressure. If it were within the power of the surgeon to keep bacteria entirely 4 
out of wounds, or to destroy them without damage to the tissues after they enter, 
the conditions just mentioned could not by themselves alone cause infection, 
but this power he does not at present possess, as is demonstrated by the bacter- 
iological examination of wounds treated aseptically or antiseptically. Hence it 
behooves him to learn all that he can concerning those conditions which favor 
and those which are hostile to the development of bacteria in wounds, and to 
endeavor to retain and produce the hostile and to remove the favorable conditions 
for the growth of bacteria. 
That conditions predisposing to suppurative and septic complications of 
wounds are to be sought not only in local conditions about the wound, but also 
in the general state of the patient, is known to every surgeon of experience, and 
this latter side of the subject has been recently presented in an interesting and 
suggestive manner by Ur. Roswell Park, in his paper before the Congress of 
American Physicians and Surgeons. 
It has been a stumbling block in the way of the acceptance of the general princi- 
ples of antiseptic surgery by some, that surgeons who claim to disregard these prin- 
ciples have good results even in operations which were considered unwarrantable 
before the introduction of antiseptic methods. The foremost champion of these 
dissenters is, perhaps, Lawson Tait, so widely known as a successful laparoto- 
mist. But there is no difficulty in explaining these results, which in reality fur- 
nish no sound argument against the employment of proper antiseptic measures 
in the treatment of wounds. Mr. Tait and his followers make extensive, 
although not sufficient, use of the most efficient of all antiseptic agents, 
namely, heat. By attention to cleanliness they greatly diminish the chances 
of infection of wounds by bacteria. They are often particularly rapid and 
skillful operators. Above all they respect the vitality of the tissues, es- 
pecially by withholding the application to them of chemical disinfectants. They 
do not disregard the principles of antiseptic surgery to the extent that they may 
suppose they do, but they would be wiser if they paid still more attention to 
these principles. Because the use of unsterilized ligatures or the washing of the 
peritoneal cavity with unsterilized water is not attended by bad results in many 
cases, is no proof that it is not safer to sterilize ligatures and all that comes into 
contact with a wound. 
Moreover, there are special reasons, now well known, why the results of opera- 
tions in the peritoneal cavity cannot be regarded as the best test of antiseptic 
methods. The healthy peritoneum is tolerant to an extraordinary degree of the 
presence of pyogenic bacteria, but when these conditions of tolerance are over- 
stepped then the dangers from infection surpass those from infections of wounds 
of external parts. These exceptional dangers are what render the employment 
of proper antiseptic measures especially imperative in laparotomies. 
The tendency at the present time to abandon the application of strong disin- 
fectant solutions to fresh wounds and to pay more attention to the gentle hand- 
ling of wounded tissues has been interpreted by some as a reaction against anti- 
septic surgery and a return to ideas which obtained in pre-antiseptic days. It 
is true that the capacity of the living tissues to resist putrefaction and the in- 
fluence upon the process of healing of the character and condition of wounds 
are very old conceptions in surgery. The old books on surgery have much to 
say on these points, and entered into extreme refinements in the classification and 
description of wounds, with especial reference to their behavior in the process of 
repair. They contained much sound doctrine in these matters, which can still be 
perused with profit. But the results of the old and those of the new surgery are alone sufficient to prove the wide difference between them. Under the old reg- 
ime the healing of wounds without suppuration was so exceptional that the oc- 
currence could even be disputed by prominent surgeons, whereas now the sur- 
geon with good technique may look with reasonable certainty to this result, once 
so exceptional. The foundations of antiseptic surgery are strengthened, not 
shaken, by improvements in details and by the recognition of new principles. 
Now that we recognize the dangers of applying strong antiseptic substances to 
wounds and the difficulties of disinfecting wounds in this way, the arguments 
are stronger than ever before for operating with as nearly sterile surroundings as 
possible and for keeping the wound from contact with unsterilized objects. 
Permit me to say in this connection that I fail to see the advantage of using 
the term aseptic surgery in the sense in which it is generally employed at the 
present time as something distinct from antiseptic surgery. One hears on all 
sides such expressions as that aseptic surgery is displacing or is destined to dis- 
place antiseptic surgery. What is understood by aseptic surgery undoubtedly 
marks an important advance in surgical antisepsis, but it is none the less anti- 
septic surgery. It would seem as if some supposed that antiseptic surgery 
means nothing more than the use of chemical disinfectants in the management 
of wounds, or that antiseptic technique is incapable of improvement. An an- 
tiseptic agent is anything which has the power of arresting the development of 
septic bacteria. With his views as to the influence of blood in a wound in favor- 
ing infection, von Bergmann has said that a ligature is one of our most import- 
ant antiseptic agents. The substitution of heat for chemical substances in the 
disinfection of instruments, ligatures, dressings, etc., is an important advance 
but it is only the substitution of a more powerful for a weaker antiseptic agent. 
The object of antiseptic surgery is to secure an aseptic condition of a wound, 
and here it may be well to remark that this rarely is equivalent to the condition 
generally understood in a bacteriological laboratory as aseptic, namely, freedom 
from bacteria. 
The abandonment of disinfectant applications to a wound is for the purpose 
of securing the act ion of more efficient antiseptic agencies under the circum- 
stances, namely, the fluids and cells of the surrounding tissues, and this 
abandonment renders all the more urgent the use of antiseptic agents outside of 
the wound. It is doubtless one of most useless occupations to contend against 
current usage in medical nomenclature, but it seems to me unfortunate that the 
term aseptic surgery should be introduced as if it signified something different 
from antiseptic surgery and not simply an improvement in the methods of anti- 
septic surgery. 
It is interesting from a bacteriological point of view to note the improvement in 
the dressing and management of wounds since the pioneer work of Lister. The 
early efforts in this direction, especially in Germany, were to render the dress- 
ings less expensive and less cumbersome, items of no small consideration in a 
hospital with limited resources. Important advances in principle, however, re- 
sulted from the efforts to do away with the frequent changing of surgical dressings, 
which w is necessitated by Lister’s early method. The employment of absorbent 
material for the dressings without the outside impermeable covering adopted by 
Lister, permits rapid drying of the secretions and, therefore, rests upon the sound 
basis that bacteria find in moist mediaopportunitiesfor theirgrowth not furnished 
by dry material. Every bacteriologist knows that his culture tubes are much 
more likelv to become contaminated if he places a rubber cup o\er the cotton-wool 
at the mouth of the tube than without this precaution, unless he takes especial 
pains to sterilize the cotton-wool and the mouth of the tube before applying the 6 
rubber. It is almost impossible for the surgeon to keep his dressings for any 
length of time free from bacteria, and it is, therefore, advisable not to shut these 
bacteria into secretions and an atmosphere saturated with moisture, prevented, by 
an impermeable covering, from evaporation. 
Some of the most important advances in antiseptic surgery have come from the 
efforts to dispense with the nse ofdrainage tubes, The drainage tube question is a 
part of the much larger one: IIow shall the so-called dead spaces, that is, the cavi- 
ties and recesses, in a wound be managed? The surgeon has at his disposal the 
choice between many various means for managing these spaces. lie can drain 
the spaces, or stuff them, with foreign material, or endeavor to obliterate them by 
pressure, or by buried sutures, or by inverting sutures, or by transplantation of 
flaps, or he can permit them to fill with blood, or he can let them alone. Doubt- 
less no one of these methods is universally applicable; probably each one has its 
field of usefulness. The skill of the surgeon consists in large measure in the man- 
ner in which he exercises his judgment as to the management of the dead spaces 
in a wound, and I shall venture to say a few words on this important but still un- 
settled question only from a bacteriological point of view. 
The following objections to the insertion of drainage tubes into wounds suggest 
themselves: First. They tend to remove bacteria which may get into a wound 
from the bactericidal influence of the tissues and animal juices. Second. Bacteria 
may travel by continuous growth or in other ways down the sides of a drainage 
tube and so penetrate into a wound which they otherwise would not enter. Me 
have repeatedly been able to demonstrate this mode of entrance into a wound of 
the white staphylococcus found so commonly in the epidermis. The danger of 
leaving any part of a drainage tube exposed to the air is too evident to require 
mention. Third. The changing of dressing necessitated by the presence of drain- 
age tubes increases in proportion to its frequency the chances of accidental infec- 
tion. Fourth. The drainage tube keeps asunder tissues which might otherwise 
immediately unite. Fifth. Its presence as a foreign body is an irritant and in- 
creases exudation. Sixth. The withdrawal of tubes left any considerable time in 
wounds breaks up forming granulations and thus both prolongs the process of re- 
pair and opens the way for infection. Granulation tissue is an obstacle to the in- 
vasion of pathogenic bacteria from the surface, as has been proven by experiment. 
Seventh. After removal of the tube there is left a tract prone to suppurate and 
often slow in healing. 
The advantage from the employment of drainage tubes is, of course, the removal 
of secretions, and this indication becomes an urgent one if the cavity with which 
the tube communicates becomes infected and suppurates. In a given case the 
surgeon must weigh the advantages and the disadvantages and act according to his 
judgment. The practice of many surgeons at the present time, of restricting within 
much narrower limits than formerly the use of drainage tubes and of discarding 
them for all wounds which offer a fair prospect of primary union, is a distinct ad- 
vance in the technique of antiseptic surgery. 
The practice of stuffing cavities with foreign substances, even those of an ab- 
sorbable nature, is open to most of the objections already urged against drainage 
tubes. 
Much can be accomplished by external pressure in bringing together the surfaces 
within a wound, but this procedure is of only limited application, for on the one 
hand only such spaces can be obliterated in this way as are favorably situated and 
have surfaces suitable for coaptation, and on the other hand there is difficulty in 
regulating the pressure so that it does not interfere with the circulation and with 
the the tissues. 7 
The method elaborated especially by Neuber and by Kiister, of obliterating spaces 
in a wound by means of deep coaptation sutures, has unquestionably given excel- 
lent results, but it is not free from serious objections. The conscientious execu- 
tion of the method often is tedious and greatly prolongs the operation, and it may 
be doubted whether the object aimed at is not often missed. The most manifest 
objections however, are the presence in the wound of so many foreign bodies in the 
form of sutures as are often required, and especially the danger of strangulating 
and stretching unduly the tissues, and thus interfering with their anti-bacterial 
capacities. The thinner the sutures employed, the smaller is the danger of their 
presence as foreign bodies. 
The idea that blood in a wound is a dangerous thing is a prevalent one, and such 
surgeons as Kiister and von Bergmann in recent years have dwelt especially upon 
this danger. Blood is looked upop as a foreign substance more dangerous than 
most foreign substances because it is held to be especially prone to decomposition 
by bacteria. Nevertheless, John Hunter was fondof dwelling upon what he called 
the vitality of blood, and was acquainted with its so-called organization in wounds. 
Mr. John Chiene, about fifteen years ago, directed attention anew to the same 
views; but it was Schede who in 1886, in an article on the Healing of Wounds Un- 
der the Moist Blood Scab, brought prominently to the notice of surgeons the value 
of the blood' clot in the healing of a certain class of wounds. The discoveries 
more recently made as to the power of fresh blood outside of the body to destroy 
many kinds of bacteria (although in only very limited degree the pyogenic cocci) 
or their poisonous products have shed additional light upon this subject. The credit 
of introducing as a method of general applicability the management of dead spaces 
by permitting them to fill with blood belongs to Ilalsted. Before him several sur- 
geons, and Schede especially, had recommended the useof the blood clot for a lim- 
ited class of wounds and for a limited purpose, but ITalsted has substituted for all 
other methods previously employed in treating dead spaces not otherwise easily oblit- 
erated, that is, for drainage tubes, buried sutures, pressure, etc., the use of the blood 
clot as the method of widest applicability and as affording the best results. In a 
paper read before the recent Congress of American Physicians and Surgeons, I de- 
scribed the results of my experiments on animals, which supported the conclusions 
derived from clinical experience as to the value of the method of healing of wounds 
by allowing spaces to fill with blood. That the unintended presence of blood in a 
wound may be a source of danger by occasioning undue tension and in other ways, 
and is a very different thing from the purposeful application of the method of 
healing by so-called organization of blood coagula, hardly needs to be mentioned. 
Nor need I emphasize the fact that loss of blood, as such, is to be guarded 
against, for it is proven experimentally that general anaemia is a predisposing cause 
of infection with pyogenic bacteria. 
The question suggests itself, what would happen under good antiseptic technique 
if the so-called dead spaces of a fresh operation wound were left to themselves, 
that is, were neither drained nor obliterated nor permitted to fill with blood ? 
There is not sufficient experience to answer this question satisfactorily. This, 
however, is to be considered. Exudations composed of fluid and cells would quickly 
accumulate in most of these spaces, and these fluids and cells possess anti-bacterial 
properties as well as blood. Granulation tissue would spring up from the sides. 
I venture to predict that if the surgeon paid no particular attention to the fill- 
ing or obliteration of many of the smaller spaces in fresh operation wounds, and 
if the antiseptic technique were good, the process of healing would be as satisfac- 
tory as by any of the other methods mentioned. 8 
Let us now turn our attention to the progress which has been made in the em- 
ployment of antiseptic agents for surgical purposes. Soon after the introduction 
of Lister’s methods, the search began for new and better disinfectants than carbolic 
acid. This search brought to light a large number of agents, some good, but 
more of little or no value for the nurpose intended, and in general, carbolic acid 
continued to possess the field until Koch, by his fundamental experiments with 
disinfectants, demonstrated the pre-eminent germicidal power of corrosive subli- 
mate. This latter disinfectant has, to a large extent, although not entirely, 
taken the place formerly occupied by carbolic acid as the surgical disinfectant 
par excellence. In no department of antiseptic surgical technique has the value 
of bacteriological methods of experimentation been more evident than in estab- 
lishing the germicidal powers of various real or supposed disinfectants; neverthe- 
less, the importance of not rejecting sound clinical experience in this matter is 
shown bv the fate of iodoform as an antiseptic agent. Iodoform would probably 
never have been recommended as an antiseptic on the basis of bacteriological ex- 
periments alone. Still, the benefits of its employment in wounds and surgical 
affections are undoubted, and a more careful study of the mode of action and 
the conditions required for the development of the antiseptic powers of iodoform 
has justified thehse of this substance. A class of disinfectants obtained by frac- 
tional distillation at high temperatures of coal-tar oils has reeently been intro- 
duced, and promises valuable service. These are the higher cresols, which pass 
overby distillation between 190° and 210°C. The difficulty has been to obtain 
these oils in a form soluble in water. Creolin is a fine emulsion of these cresols; 
and lysol, a solution of the same in water by a soap combination. Although, 
like most new disinfectants, creolin and lysol have not sustained the extravagant 
claims made for them by their early enthusiastic advocates, nevertheless they 
possess strongly disinfectant and other valuable properties and are a useful con- 
tribution to the list of surgical antiseptic agents. 
But surgical disinfection has progressed not so much by the introduction of 
new chemical disinfectants as by a better understanding of the mode and condi- 
tions of their efficient action. It was once supposed that the skin, wounds, in- 
struments, sponges, etc., could be completely disinfected, without any especial 
precautions, by being placed fora short time in the disinfectant solutions. Mis- 
leading inferences were drawn from the powerful germicidal action of chemical 
disinfectants when brought into contact with bacteria under the most favor- 
able conditions, namely, with bacteria on silk threads or suspended in water. 
Not sufficient attention was paid to one of the most important results of Koch’s 
investigations of disinfectants—that the presence of oil or fat prevents the para- 
siticide action of' chemical disinfectants. From this it should have been clear 
that the presence of oily substances in the epidermis, and often, also, on instru- 
ments, sponges and other objects used by the surgeon, must frequently render 
his efforts at disinfection nugatory, unless by the use of alcohol or by thorough 
mechanical scrubbing with soap and water, he first removes the grease. Hence 
it might easily happen that those who scouted the use of chemical disinfectants 
but employed thorough mechanical cleansing of hands, instruments, etc., really 
attained a higher degree of antisepsis than those who trusted exclusively to chem- 
ical disinfection. Thorough mechanical cleansing and scrubbing with soap and 
water, although it accomplishes much, does not generally bring about complete 
disinfection and cannot, therefore, alone be trusted, but these measures are essen- 
tial adjuvants of any method of surgical disinfection with chemical agents. It may 
be mentioned that the alkaline soaps possess some disinfectant power, often quite 
as much as especially prepared commercial disinfectant soaps. The differences in germicidal power of corrosive sublimate under different condi- 
tions are much greater than those of carbolic acid and most other disinfectants. 
Aside from the presence of oily material, the great obstacle against the disinfect- 
ant action of corrosive sublimate in the animal tissues and fluids is its precipita- 
tion with albuminous substances. So great is the obstacle that it may be doubted 
whether it is possible to disinfect by means of corrosive sublimate wounds in- 
fected with bacteria, and whether irrigation with solutions of corrosive sublimate ac- 
complishes much more in this way than that with sterile salt solution. We owe 
especially to Geppert the demonstration that former methods of testing the ger- 
micidal power of corrosive sublimate were subject to such grave errors that their 
results cannot be trusted. Geppert has shown that it is necessary to get rid of the* 
sublimate, which can best be done by precipitation with sulphide of ammonium (or 
other alkaline sulphides), in order to determine whether bacteria subjected to its 
action have actually been killed or not. When this precaution is taken it is found 
that corrosive sublimate is a far less energetic disinfectant than has been generally 
supposed. For example, Koch believed from his experiments that corrosive sub- 
limate in the strength of 1-1000 destroys anthrax spores in one minute, whereas 
Geppert has shown that the same strength of sublimate may not have killed all of 
the spores in watery suspension even at the end of 72 hours. In a recent article 
Geppert has shown that it is really very difficult to determine whether all of the 
spores are killed or not by sublimate, inasmuch as a definite concentration of the 
solution of sulphide used for precipitation is required to test this point and the 
failure to obtain cultures or to infect an animal is no proof that the spores have 
been killed, for a different concentration of the substance used to precipitate the 
sublimate or the employment for this purpose of some substance less injurious to 
the spores might demonstrate still greater resistance against sublimate. Dr. 
Abbott has gone over the question of disinfection of the staphylococcus pyogenes 
aureus with corrosive sublimate in my laboratory and his results in conformity with 
those of Geppert for other bacteriahave been made known to you. It may be that 
the powerful inhibitory and attenuating action of corrosive sublimate upon bac- 
teria is all that is required for the purposes of the surgeon, but it should be 
understood that this is not equivalent to disinfection, which means the actual de- 
struction of bacteria. 
In view of the difficulties and uncertainties of securing under many conditions 
complete disinfection with chemical agents, especially with corrosive sublimate, it 
marks a great progress in surgical antisepsis that heat, in the form of dry heat, 
or live steam, or boiling, is now used so extensively by the surgeon for steriliza- 
tion of instruments, ligatures, dressings, etc. That chemical disinfectants still 
have and are likely to continue to have important uses in surgical practice goes 
without saying. 
As I have recently, before the Congress of American Physicians and Surgeons in 
Washington, presented some of the results of our experience with methods of disin- 
fection of the skin, I shall utilize the present occasion to demonstrate to you a num- 
ber of culture tubes which illustrate the results of experiments begun by Dr. Hal- 
sted, and carried farther by Drs. Ghriskey and Robb, in my laboratory. 
A fact important to know in connection with experiments on cutaneous disin- 
fection is that the mercury, probably in combination with albuminous material, re- 
mains for many days in the epidermis of hands which have been frequently washed 
in solutions of corrosive sublimate in the manner customary with surgeons, and 
this notwithstanding the ordinary daily ablutions with soap and water. Of this I 
will ask any surgeon present who uses frequently corrosive sublimate for disinfec- 10 
tion of his hands to convince himself by placing his fingers in this solution of 
ammonium sulphide. A mere brownish discoloration of the surface of the skin 
after applying ammonium sulphide must not be taken as evidence of the presence of 
mercury, for this in varying degree can take place with those who have not been in 
contact with mercurial solutions, but it is the rapid deep brown or black discolor- 
tion, especially of the nails, which indicates the formation of sulphide of mercury. 
A pretty demonstration of the growth of the nails is furnished by the absence of 
the dark brown color in the part of the nail which has grown since the use of the 
sublimate-solution. Not only may the mercury remain for a long time in the 
epidermis, but it is capable of presenting the growth of bacteria with which it 
originally came into contact when scrapings from the epidermis are placed in 
nutrient agar or gelatine. It does not, however, seem to exert any such inhibi- 
tory action upon bacteria which have become attached to the epidermis after the 
application of the sublimate. That epidermal bacteria which fail to grow in 
culture media inoculated with scrapings from the surface of the skin after wash- 
ing with sublimate solutions are not necessarily dead, is proven by their develop- 
ment when the scrapings are taken from the same skin after precipitation of the 
mercury in the epidermis with sulphide of ammonium. For this result the ex- 
periments of Geppert had already prepared us, and it is the failure to precipitate 
the mercury with an alkaline sulphide which led Furbringer to apparently better 
results than we have obtained in testing his method of disinfection of the hands 
with corrosive sublimate. It is also clear that erroneous conclusions may be 
derived from testing the germicidal power of any other disinfectant on the skin, 
if the hands of those who are in the habit of using sublimate solutions on them 
be selected as the object of disinfection, unless the precaution be taken first to get 
rid of the sublimate, which is best done by precipitating it as the sulphide of 
mercury. 
If the hands have been washed, say the day before, in a solution of corrosive 
sublimate, then it may happen that most or all of the bacteria which have become 
attached to the skin since then can be removed by simple scrubbing with soap 
and water, or by some solution the disinfectant powers of which it is desired to 
test, and the cultures made from scrapings of the epidermis prove sterile. That, 
however, there are still living bacteria in the superficial layers of the epidermis, 
maybe shown by making the cultures after washing the hands in solutionsof am- 
monium sulphide. It is probable, from Geppert’s recent work, that we should 
have obtained even more striking results if we had paid more attention in the 
experiments to the concentration of the solutions of sulphide of ammonium, 
but we were not familiar then with the importance of this point, and, as it is, 
the results were sufficiently striking. 
I show you here a series of cultures which are intended to demonstrate the 
points mentioned. Scrapings from the epidermis or beneath the nails were made 
with a sterilized knife constructed for the purpose, and were transferred to lique- 
fied agar, which was then rolled or poured into Petri’s dishes. 
In this first series of agar roll cultures there are three sets of tubes which have 
been inoculated with scrapings from the epidermis and beneath the nails of one 
of the assistants in the hospital who is in the habit of making daily use of sub- 
limate solutions. The first set were inoculated with scrapings without any pre- 
liminary treatment of the hands; the second after thorough scrubbing with soap 
and warm water by means of a sterilized brush; and the third after washing the 
hands, subsequent to the scrubbing with soap and water, with a solution of sul- 
phide of ammonium, which brought out a deep brown or black color of the epi- 11 
dermis and nails. You will observe that all of the tubes of the first set contain 
a large number of colonies, that two of the tubes of the second set contain no 
colonies and two contain from three to ten colonies, and that the tubes of the 
third set contain from twenty to one hundred colonies. 
In this secoud series of agar roll cultures, intended to show the results of Fiir- 
bringer’s method, the experiment has been made with hands which have not 
previously been in sublimate solution. The first set of tubes were inoculated 
with scrapings from beneath the nails without preliminary treatment; the 
second after thorough scrubbing with soap and water; the third after the use of 
alcohol, and then washing in sublimate 1-500 for two minutes; and the fourth 
after washing the hands in sulphide of ammonium, which turned them dark in 
color. Each step was carried out strictly according to Fiirbringer’s directions, 
and double the amount of time which he recommends given to each step. The 
sublimate was freshly prepared in distilled water. The hands were well washed 
in sterilized water and then dried with a sterilized cloth before inoculating the 
third set of tubes. Each set was inoculated with the scrapingsfrom beneath and 
around the nails and placed in the thermostat at 37°0. You will observe that 
the first set of tubes are crowded with colonies; that the second contain a smaller 
number, but still a good many colonies, from twenty to over a hundred; that the 
third set are sterile, save one colony in one of the tubes; and that the fourth set 
contain some colonies in each tube, varying from three to twenty-five. Fur- 
bringer inferred from such results as those in the third set of tubes that the sub- 
limate had actually killed all of the bacteria in the superficial layers of the epi- 
dermis and beneath the nails, whereas, if he had precipitated the mercury with 
ammonium sulphide as was done before inoculating the fourth set, he would have 
learned that this is not the case. It is fair to say that we have sometimes ob- 
tained sterile tubes by Fiirbringer’s method, even after precipitation with am- 
monium sulphide, and we do not intend to condemn the method as not a good 
one, but only as not the best, and as not accomplishing all that is claimed for 
it. As has already been said, it may be that it is sufficient to inhibit the growth 
of the bacteria in the way that is done by the sublimate, but it is not justifiable 
to infer that because the bacteria will not grow in our culture media they may 
not grow in the animal body. It is also to be considered that sublimate is capa- 
ble of attenuating or destroying the pathogenic power of some bacteria. But 
even after giving due weight to these considerations, that method which actually 
kills the bacteria is to be preferred if it is applicable. 
The third series of tubes has been inoculated with scrapings from beneath the 
nails after disinfecting the hands with lysol; and the fourth after disinfection 
with peroxide of hydrogen, the preliminary scrubbing with soap and water being 
as in the other experiments. You will observe that neither of these agents has 
accomplished complete disinfection, there being a few colonies in most of the 
tubes, the most in the tubes after using peroxide of hydrogen. The hands were 
disinfected with lysol in the manner recommended by Gerlach. 
On the other hand, in this fifth series of tubes inoculated with scrapings from 
beneath the nails after disinfection with permanganate of potash and oxalic acid 
in the manner described in my paper before the Congress in Washington, you 
will observe that all of the tubes are sterile with the exception of one colony in 
one of the tubes. We, therefore, have adopted in the hospital this method of 
disinfection of the skin. Whether there may lurk some fallacy in the conclu- 
sions which we have drawn from our experiments with this method analogous 
to that in previous experiments with corrosive sublimate I cannot say, but if so, 
we have not been able to detect it. 12 
Our experiments with methods of cutaneous disinfection, as well as our ob- 
servations on the bacteria in wounds treated antiseptically, have led us to a 
study of the bacteria in the skin. The micro-organisms in the human epidermis 
have been studied by a number of investigators, as Bizzozero, Bordoni-Uffreduzzi, 
Unna, Maggiora, Mitmann and Premdlsberger, and a large number, over a 
hundred different species, have been more or less perfectly described. Our pur- 
pose has been not to make a complete study of the bacterial flora of the skin, 
although we do not regard such a study in the light of Fiirbringer's characteri- 
zation of it as a“zeitraubende, geistestodtende, wenig fordernde Beschaftigung,” 
but rather to learn something about the frequency of occurrence of the most 
common pyogenic cocci, about the most common bacterial inhabitants of the ep- 
idermis and about the possibility of the presence of bacteria in layers of the epi- 
dermis not reached by existing methods of cutaneous disinfection. 
In conformity with Fiirbringer’s statements as to. the relation between the 
occupation of an individual and the bacteria present beneath the nails, we have 
found the staphylococcus pyogenes aureus only very exceptionally in the epi- 
dermis or in the subungual dirt of those who have had nothing to do with sup- 
purating wounds, abscesses or other surgical cases, but on the other hand have 
found this organism repeatedly on the skin or beneath the nails of surgeons or 
their assistants. The bearing of these observations are sufficiently apparent to 
need no further emphasis. 
We have found a white staphylococcus far more frequently than any other organism 
in the epidermis and beneath the nails after the superficial bacteria have been re- 
moved by scrubbing the hands with soap and water or by incomplete disinfec- 
tion, as by washing with sublimate. Unna and others who have studied by cul- 
ture methods and have paid attention to the relative frequency of the different 
kinds of bacteria on the skin have also noted the frequency of occurrence of a 
white coccus liquefying gelatine. Unna regards this most common coccus as 
the staphylococcus pyogenes albus. We have observed that this common epi- 
dermal staphylococcus liquefies gelatine and coagulates milk more slowly than 
the typical staphylococcus pyogenes albus, and that a centimeter and more of 
bouillon cultures can be injected without effect into the veins of rabbits. 
Whether this coccus is a distinct species or only a modified form of the staphy- 
lococcus pyogenes albus, we have not been able definitely to decide, but I have 
proposed for it, provisionally, the name staphylococcus epidermidis albus. Other 
white cocci also occur in the skin. We have met, several times, forms correspond- 
ing to the micrococcus cereusalbus (Passet), the micrococcus candicans (Fliigge) 
and the micrococcus albus liquefaciens (v. Besser). Von Besser has found in 
the normal air passages a white staphylococcus resembling the staphylococcus 
pyogenes albus save by the absence of pathogenic properties. In general, the 
classification of the white liquefying micrococci is difficult and unsatisfactory. 
There are differences in the rapidity of liquefaction of gelatine by our staphy- 
lococcus epidermidis albus and occasionally we have isolated forms which cor- 
respond in mode of growth to the staphylococcus pyogenes albus, but have not 
isolated any with the pathogenic powers of this coccus, so far as we have been 
able to test this point. We have also occasionally found in the epidermis a 
staphylococcus resembling closely, in the appearance of its colonies on agar and 
its scarcely visible growth on potato, the typhoid bacillus. 
We regard as the most important outcome of our studies of the bacteria of 
the skin the demonstration of the presence of the staphylococcus epidermidis al- 
bus, lessfreqently of other bacteria, in layers of the skin deeper than can be reached 
by existing methods of disinfection of the skin. The significance of this fact is 
apparent when I tell you that this same coccus is the one which we have found 13 
in a very large number of laparotomy wounds treated by the most careful anti- 
septic or aseptic metnods and that it is the most frequent cause of stitch ab- 
scesses. We have found it so in the deeper layers of the epidermis that 
we are inclined to consider it a regular inhabitant of the skin. It has only 
feeble pathogenic power ordinarily, but it is capable of causing suppuration. 
The injurious influence of a drainage tube in checking the repair of fresh 
healthy wounds is illustrated by the fact that it is chiefly in wounds containing 
drainage tubes that we have observed suppuration to result from the pres- 
ence of this organism, and that often the suppuration is limited to the track oc- 
cupied by the tube. This coccus is found not only in stitches around which 
suppuration has occurred, but also in those without any visible inflammatory 
reaction around them. 
I show you here a number of cultures of this organism. These three cultures 
were made in the following way: the skin of a patient before an operation was 
thoroughly disinfected bv the method already described, so that scrapings from 
the surface afforded no growth, then by means of a sterilized instrument; steri- 
lized silk threads (tested by cultures), were drawn from one to five or six times 
through the disinfected skin and these silk threads were then dropped into lique- 
fied agar, the tubes were agitated and then rolled on ice. You will observe that 
several white colonies (varying from two to ten), and eoalescent colonies have 
developed, especially along the sides of the thread. The remaining five agar roll 
cultures have been inoculated with silk sutures removed from the skin, four to 
seven days after antiseptic laparotomies, pursuing in each case a perfectly aseptic 
course and without any evidence of inflammatory reaction around the stitches. 
Each of these tubes contains colonies of the white staphylococcus, varying from 
six to fifty in number. 
We have found also other bacteria, and twice the staphylococcus pyogenes aureus, 
in skin stitches withdrawn after antiseptic operations, but the staphylococcus 
epidermidis albus is by far the most common. To judge from the number of 
colonies developed from sterilized threads drawn through the skin after complete 
disinfection of the surface it would seem as if the white staphylococcus were net 
particularly abundant in the epidermis. Further investigations, which must be 
microscopical, are necessary to determine the exact part of the epidermis or hair 
follicles or glandular appendages of the skin occupied by these bacteria, and here 
the methods recently described by Unna are likely to be of service. 
I hardly need to say that these observations on the bacteria of thenormal skin, 
and the depth to which they penetrate, indicate that the skin of the patient may 
be a source of wound infection and that the surgeon should take greater pre- 
cautions than has hitherto been customary, to guard against this danger Dr. 
Halsted, in view of our results on cutaneous disinfection, has discarded for the 
most part the use of cutaneous sutures, and is very well satisfied with the results 
obtained by bringing the edges of wounds together by subcutaneous sutures. 
I have endeavored, gentlemen, to bring before you, although in a disconnected 
way, a few of the improvements in antiseptic surgery since Lister’s pioneer work, 
as they present themselves to one looking at the subject from a bacteriological 
point of view. Surely progress has been great, but there is no reason to suppose 
that the ideal has yet been reached and that there is not room for further ad- 
vance. Even in directions where it now seems to us that the goal is attained we 
must be guarded in our predictions, lest we make ourselves as ridiculous to future 
generations as to us seems the leading surgeon of his day, Boyer, when in the 
early part of this century he wrote ‘‘Surgery in our day has made the greatest 
progress and appears to have attained, or nearly so, the highest perfection of 
which it is capable.”