ILLINOIS STATE DAIRYMEN’S ASSOCIATION. 
85 
01 these organisms a glass of excellent definition was required, and a 
power of at least eight hundred diameters. Yeast cells (of bread) 
are mountains compared with them. If any living things find their 
way through the animal tissues and escape, as with the milk, we may 
safely conclude it is something of this description. There is no 
evidence that higher and larger fungi as ordinary molds are ever 
developed from the minute forms described. 
t 
Y hen fresh milk from healthy cows is placed under a high 
magnifier (500 to 1,000 diameters) the thin stratum appears violently 
agitated by currents caused by evaporation, etc., and by the molecu¬ 
lar, oscillating motion known as the Brownian movement, but no 
bacteria can be found. Examine the same milk after it has stood in 
a Warm place a few hours, and before evidence of acidity except to 
litinus paper is presented, a few bacteria may be observed ; before 
coagulation they are quite common and finally become in some cases 
excessively numerous. Milk put in well-stoppered, scalded vials 
kept in a temperature of from 80° to 90° Fahr. sometimes becomes 
very sour but suffers no further change. But frequently after souring 
the inclosed liquid becomes putrid and highly odoriferous. Upon 
examining two such as these the difference can be ascertained. The 
former contains one kind of bacteria, the latter two. The first is at 
the outset minute and spherical or cylindrical and composed of 
joints which are often more or less bent upon each other. Its move¬ 
ments are of an oscillatory character, with slight or no progress in 
any direction. The second is not unlike the first in shape, though 
not so distinctly composed of easily-separated joints, but it moves 
with an endwise sliding motion of apparently, under the microscope, 
great rapidity. One is the lactic ferment, the other is the putri- 
factive ferment. They may occur together or either may exist with¬ 
out the other. But the lactic organism appears either more common 
or more active in its work. 
In one experiment three vessels were placed in the same tin 
vessel which closed tightly. Milk fresh from a cow was placed in all 
of the inclosed vessels, which were of glass with open top. In 
number one the blade of a pen-knife was dipped which had previ¬ 
ously been inserted in sour milk swarming with the lactic ferment. 
In number two a minute amount of milk just coagulated was placed, 
and number three was left as it was. Coagulation took place in 
the order named with about two hours intervening between the first 
and second and six hours between the second and third. After two 
