278 ON THE GERM THEORY OF PUTREFACTION 
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 lining membrane ; 
and the intervals between acts of micturition would afford time for the organ- 
isms to spread extensively inwards if it were a tube of indifferent matter ; but 
I hoped, in accordance with the principle which I had had reason on other 
grounds to believe in, that the organisms would prove unable to develop in 
this putrescible material, however favourable a nidus for their growth. If this 
were really the case, instead of having the urine drawn off with a catheter, with 
special precautions, as was done by a surgeon at Pasteur’s request, if the skin 
round the orifice of the urethra were treated with an efficient antiseptic, say 
with a solution of carbolic acid in forty parts of water, the urine might then be 
passed from the patient from whom it should be obtained, perfectly uncontami- 
nated, though unboiled, free from any living organisms. Accordingly, on the 
16th of November, 1871, I performed the following experiment :—Six wine-glasses 
were heated far above the temperature of boiling water by means of a spirit- 
lamp. I may here remark that in the rest of this communication, wherever 
I use the word ‘ heated’ (in quotation marks), I shall wish to be understood as 
meaning that the thing spoken of is not hot when used, but that it has been 
heated far above the boiling point of water, and then allowed to cool. Six 
glasses, then, were thus prepared, ‘ heated’ by means of a spirit-lamp. A glass 
plate large enough to cover them all, and overlap them considerably, was also 
similarly ‘heated’. Urine was then passed into these six glasses with the 
antiseptic precaution that I have mentioned. Two of the glasses, before being 
covered, received each a minim of water from the tap ; and into a third a much 
smaller quantity of water was introduced. To the rest no water was added, but 
one was left exposed for twenty-four hours to the air of my study, while the 
other two were put at once under the cover of the glass plate. After the lapse 
of forty-eight hours, quite in accordance with Dr. Sanderson’s statement, the 
two to which the drops of water had been added were turbid from the develop- 
ment of large and active bacteria ; and the one which received a very minute 
quantity of water was similarly affected, though in a less degree, while the other 
glasses showed no change. But when twelve more hours had passed, the glass 
which had been exposed to the air, without the addition of any water, presented 
spots of opacity in the cloud of deposited ‘ mucus ’, and on examining a portion 
of the cloud with the microscope, I found in the first field several bacteria in 
full activity. But the other two which had been covered by the glass plate 
