324 PROFESSOR LISTER ON THE GERM THEORY 
a minim of the urine in the test-tube, including some of the white deposit at the 
bottom. The glass, which was of course “ heated,” as well as its porcelain cap, 
was placed under a glass shade in a room varying in temperature from about 
60° to 70° F. It is necessary to state, that before raising the inverted test-tube 
which covered that containing the urine, I carefully wiped the mouth of the 
former with a rag dipped in a strong watery solution of carbolic acid ; without 
this precaution there would have been a risk of contamination of the urine-tube 
with some portion of cotton or dust adhering to the covering tube.* The 
urine still continued quite bright, and on examining with the microscope the 
residue in the pipette after the inoculation, I found it to consist of the oval 
torula unmixed with anything else. 
Thirty-six hours after the inoculation I found the inside of the glass that 
contained the Pasteur’s solution sprinkled over from top to bottom with a fine 
granular deposit resembling white sand under a pocket-lens, and about a third 
of the surface of the liquid was occupied by a dense white scum which micro- 
scopic examination on the following day showed to consist of oval torula cells, 
closely resembling those in the urine of inoculation. A group of these from the 
PasTEvr’s solution is represented at a, Plate XXIII. On the 3d January 1872, 
I inoculated a second “heated” and covered glass of the same stock of 
Pastevur’s solution by introducing into it a drop from the former glass of the 
same fluid containing the growing organism, and in the course of the next 
twenty-four hours the cells of Torula Ovalis were again seen under the micro- 
scope in a deposit on the side of the glass. Next day, beg about to return 
to Edinburgh, I introduced some of the contents of this second glass of 
PasTEvr’s solution into a “heated” test-tube provided with an inverted test- 
tube cover, and packed the tube with cotton-wool in a box along with that 
containing the urine. Meanwhile, although eleven days had elapsed since the 
urine was decanted into the test-tube for the journey south, the liquid remained 
perfectly transparent, and showed no appearance of any other organism besides 
the Torula Ovalis; so that it may be assumed that the plants of filamentous 
fungi present in the original urine-glass had been avoided in the process of 
decanting, and that the Torula Ovalis existed in the test-tube unmixed with 
any other organism. 
Being occupied with other matters, I did not look at these test-tubes again 
until eight months had passed, during which time they had remained undis- 
* The efficacy of a strong watery solution of carbolic acid for the destruction of minute organisms 
was familiar to me from experience in antiseptic surgery; and it is also well illustrated by the method 
of obtaining uncontaminated unboiled urine described.in the text. The fact is of great value in experi- 
ments on this subject, as it affords a simple and sure mode of purifying portions of apparatus which it 
would be inconvenient or impossible to subject to heat. And the extensive experience which this 
investigation has involved, enables me to state with confidence that wiping a piece of glass with a rag 
moistened with a solution of carbolic acid in twenty parts of water as efficiently ape adhering — 
organisms as heating to redness in a flame. : 

