320 PROFESSOR LISTER ON THE GERM THEORY 
could not now perform the same experiments with the same success as in the 
first instance: any that I tried was sure to be followed by the development of 
this pervading organism. I eluded it, however, by continuing the investigation 
in a room at the top of the house, which had been for a considerable time 
unoccupied. Here the results of experiments corresponded with those origin- 
ally obtained in the study. 
But I have not yet spoken of the two glasses of the second experiment 
which were not exposed, but were kept covered with the evaporating dishes 
under a glass shade. The liquid in both these glasses having remained unaltered 
for nearly a fortnight (thirteen days), I exposed one of them to the air for nine 
hours in my study, which is a warm room (over the kitchen), the weather being 
dry and frosty, and then replaced it, covered as before, under the glass shade, 
having previously ascertained that the odour was that of perfectly fresh urine. 
Two days later the cloud of mucus presented a multitude of vertical white 
streaks, and the side of the glass was also similarly marked, and when another 
day had passed the whole liquid was manifestly turbid, and there were also 
two little patches of scum upon the surface. On microscopic examination I 
found that the scum was composed of a species of torula, and that the turbidity 
was due to a small organism which, while motionless like granuligera, resem- 
bled bacteria in its mode of segmentation and arrangement. It is represented in 
the sketches given atc in Plate XXII fig. 3, where it will be observed that when 
three elements exist together they are in a straight line, and that some of those 
which are in pairs present a transverse line of incipient division through each 
constituent portion. Occasionally this organism was met with in the form of 
long chains (Leptothrix), and it is plainly referable to the bacteric group. But 
no filamentous fungus occurred from first to last in this glass, which, in that 
respect, was the exact converse of the one which was exposed to the atmo- 
sphere in the first instance for forty minutes, and in which, it will be remembered, 
filamentous fungi occurred without either torule or bacteria—the obvious 
explanation of the difference being that different organisms happened to prevail 
in the air of the room at the two periods of exposure. 
The other glass was left permanently covered ; and the urine in it remained ~ 
permanently free from organic development or putrefactive alteration. After 
the lapse of many weeks, when its bulk had been considerably reduced by 
evaporation, it became turbid, leading me to suspect bacteria. But on apply- 
ing the microscope I found the appearance was occasioned merely by saline 
deposit, and the contents finally dried up into a solid residue, without under- 
going any other perceptible change. 
I need hardly point out how entirely such a fact as this disposes of the 
oxygen theory as regards this particular fluid at ordinary temperatures. 
Neither cover nor shade fitted closely, so that a constant interchange was 

