362 ON THE LACTIC FERMENTATION PR 
rounded form, more or less oval, with the long diameter in the direction of the 
length of the chain, and often showing, on careful focusing, a line across their 
central part indicating transverse segmentation. They vary in diameter, as 
I shall have occasion to notice again, full-sized specimens measuring about 
1-20,000th inch.t You always find them, as far as I know, in souring milk 
from a dairy, and a touch with the point of a needle which has been dipped into 
such souring milk will induce their development with great rapidity in a glass 
of boiled milk, together with the characteristic curdling and souring, showing 
that the boiled milk is thoroughly disposed to the lactic fermentation as 
soon as the appropriate ferment enters, while that ferment, as already stated, 
is not likely to occur as the 
result of exposure to the air 
of your study or any ordinary 
situation. 
These little glasses (repre- 
sented on a reduced scale in 
Fig. 7) illustrate the same 
point as regards unboiled milk. 
Each is a small test-tube pro- 
vided with a cap made of the 
bottom of a larger test-tube, 
and arranged along with five 
others in a stand made of 
pieces of glass tubing and 
stout silver wire, and placed 
acne under a common glass shade 
ona plate of glass. Four such 
sets of glasses, making twenty-four glasses in all, were purified by heat in the hot 
box, together with their plates and shades. Another larger glass, provided with 
a glass cap, having been also purified by heat in the box, milk was drawn directly 
into it from a cow standing in a little orchard belonging to a dairy farm and 
within two yards of the dairy itself, the glass cap being removed immediately 
before the milking commenced, and reapplied as soon as the vessel was charged, 
the quantity amounting to about two ounces. Then by means of a syringe 
connected with a purified pipette the milk was at once transferred, in a room 
in the farm-house, to the little glasses, each cap being replaced as soon as the 
glass was charged. Yet in spite of the care that was taken, organisms must have 
* In giving these as the characters of the Bacterium lactis, I do not wish to be understood as stating 
that this species can always be certainly recognized by its morphological features alone. 
