AND ITS BEARINGS ON PATHOLOGY 367 
Microscopical Journal, an account of the behaviour, as I supposed, of the Bac- 
tertum lactis in different liquids. I stated that, having obtained souring milk 
from a dairy, I inoculated a glass of uncontaminated unboiled urine with a small 
drop, and the result was the development in that liquid of organisms with a 
very different appearance from the bacteria which I had seen in the souring 
milk. The latter had the characters of Bacterium lactis, as already described 
(Plate XIV, Fig. 9), viz. pairs or chains of small oval bodies, with lines of trans- 
verse segmentation. Those in the urine, on the other hand, were broad and 
extremely long, often coiled up like a spirillum, though motionless, like the 
Bacterium lactis. There were, however, what certainly looked like transitional 
forms between the two. From this urine I inoculated another glass of the same 
liquid, the result being a reproduction of the same large spirillum-like organism. 
I next inoculated from the second urine-glass one of Pasteur’s solution ; and 
now obtained appearances different from any before seen, viz. instead of either 
the motionless chains of Bacterium lactis of the milk, or the spirillum of the 
urine, an actively moving minute double bacterium. But on introducing a 
small drop of the Pasteur’s solution so peopled into a third urine-glass, I got 
back large coiled organisms resembling those of the former glasses of the same 
fluid, except that these exhibited languid motion. Yet the introduction of 
a small drop from this third urine-glass into one of pure boiled milk was followed 
by souring and curdling just as if the inoculation had been made with sour 
milk from the dairy. The apparently transitional forms in the first urine-glass 
made me suppose that the spirillum was the Bacteriwm lactis, modified by its 
new habitat. I also examined in a cultivating glass, under the microscope, 
a drop of a mixture of fresh urine with a small quantity of the Pasteur’s solution 
containing the moving bacteria, and found that the minute active organisms 
first seen gave place to larger languidly moving specimens, and thus I thought 
I had evidence of a transition from one to the other. And lastly the efficiency 
of the contents of the third urine-glass as a lactic ferment, in spite of the various 
forms assumed in the various media, confirmed my belief that I was observing 
one and the same organism in all the glasses. And if this was really the case, 
considering how thoroughly the organism must have been washed in the various 
media of all chemical material that might be supposed to be originally associated 
with it in the milk—particularly considering that the lactic fermentation does 
not occur at all in either urine or Pasteur’s solution—the chain of facts appeared 
a strong confirmation of the view that this particular bacterium was really the 
cause of the lactic fermentation. I was mentioning these facts a few months 
ago to an eminent physiologist, who took the view that after all bacteria might 
* See Quarterly Journal of Microscopical Science, October 1873 (p. 309 of this volume), 
