
136 THE EVOLUTION OF LIFE 
experiments showed that a slight excess of liquor 
potassee tended to retard or even prevent the occur- 
rence of fermentation, though a quantity of liquor 
potassee notably below that needed for neutralisation 
was found to be efficacious in inducing it, and that, 
too, almost as rapidly as if the neutralisation had 
been complete. Even when the liquor potasse was 
added in quantity only sufficient for half-neutralisa- 
tion, fermentation still took place in many instances, 
though in such cases the result was usually delayed 
for five or six days. 
In all these trials it was found that the fluid, 
when turbid, was not fcetid; its odour was for the 
most part scarcely at all altered, though at times it 
was rather more marked than usual. The organisms 
found in the fermenting urine were in all cases the 
same, viz. Bacilli, either short, medium size, or in 
the form of long threads (see Fig. g)—and not the 
totally different minute ferment thought by Pasteur 
to be the invariable cause of the conversion, 
in urine, of urea into ammonic carbonate and 
water.!. Sometimes only the short unjointed rods 
were found, though more frequently these were 
mixed with varying amounts of longer Vibrio-like 
bodies, and with threads such as I and others have 
generally spoken of as Leptothrix. 
The results of the foregoing preliminary experi- 
ments induced me to seek other, stricter methods, 
free from possible sources of fallacy which might be 
thought to have influenced the results. 
1 Ann. de Chim. et de Phys., t. \xiv. (1862), p. 50. 
