EE EE en 
OF PUTREFACTION AND OTHER FERMENTATIVE CHANGES. 315 
By this second fact he explained the first. If bacteria are deprived of all 
vitality by dryness, then it seemed comprehensible that the dust of the air 
should contain no living bacteria, and, therefore, that none should have grown 
in the PastEur’s solution exposed to the atmosphere in the experiment first 
mentioned. 
Further, Dr SANDERSON was led to conclude that bacteria were the sole 
causes of putrefaction ; that fungi could only cause mustiness, or a compara- 
tively insignificant alteration in organic substances. | 
Now, if these conclusions were strictly correct, they would affect my surgical 
practice in a most important manner. If it were true that the air does not 
contain the causes of putrefaction, then it would not be necessary for me, in 
carrying out the antiseptic system of treatment, to provide an antiseptic atmo- 
sphere. All that would be needful would be to purify the surface of the skin 
of the part to be operated upon by means of some efficient antiseptic, to have 
my own hands, and those of my assistants, and also the instruments, similarly 
purified ; and then the operation might be performed without the antiseptic 
_ spray which we now use, and no one would rejoice more than myself to be 
able to dispense with it. 
At the same time, striking as Dr SANDERSoN’s facts were, I could not believe 
_ the truth to be exactly as he stated—that “no amount of exposure has any 
effect in determining the evolution of microzymes” (bacteria).* Various con- 
siderations, including circumstances that I had witnessed in surgical practice, 
made me fear the news was too good to be true. I determined, therefore, to 
put the matter to the test by a very simple experiment. 
The fluid which I used was urine, which has so often been made the subject 
of experiments by PAsTEuR and others; but instead of employing boiled urine 
for the purpose, I thought that in all probability the fluid might be obtained 
unboiled, yet uncontaminated, by a very simple procedure. According to a 
principle which I enunciated about two years ago before the Royal Medical 
Society here,t and of which I must not now give any more evidence than the 
fact that will immediately follow,—the healthy living tissues are capable of pre- 
venting the development of these low organisms in their immediate vicinity. 
If that were true, although undoubtedly the skin in the neighbourhood of the 
meatus urinarius must contain such organisms, yet supposing the urethra to be 
in a state of perfect health, the tissue of the lining membrane should prevent 
the entrance of those organisms, even for the thousandth part of an inch, within 
the mucous canal. The urethra, of course, contains putrescible materials, 
whether it be residual urine or the mucus secreted by the ling membrane; 
* See Microscopical Journal, vol. xi. page 338. 
+ In an address delivered after the author had been elected an honorary member of the 
Society. 
