240 BACTERIA. 
filaments. A week later, this yeasty liquid was changed 
to a semi-solid mass, much like pure gelatinein consist- 
ence and color. Under the microscope the same bacilli 
were seen, many as isolated cells, some growing from 
spores,and some in turgid vacuolate filaments. Upon the 
same potato there afterwards appeared a smooth white 
growth, resembling somewhat, in its external appear- 
ance, the zooglw@a formed by the white bacillus previ- 
ously described as species a. In making slides from 
this, a finely granular or gritty character was noticed 
when a minute quantity of the material was pressed be- 
tween two cover glasses. These slides showed the micro- 
scopical characters as before described. Many cells 
measured .7uby 2-34. Many others in rapidly grow- 
ing filaments were much larger. 
Bacillus, species c. A very old culture of Febru- 
ary 5, from the main building showed a curious mixture 
of colors. It was an interesting study to watch the 
struggle for existence going on among the different 
forms as they successively appeared and disappeared. 
On March 15, a brilliant line of red, one centimeter long, 
was observed. A fresh potato was carefully inoculated 
with a very minute quantity of this zoogloea, and on the 
second day afterward, the cut surface was entirely 
covered with the bright red growth. Through many 
transfers, as well as in the cultures of the date men- 
tioned, this species afterward maintained its distinct 
character. The zoogloa was at first fluid and glistening, 
but an exceedingly fine-film rapidly developed over 
the surface. The color varies from orange to vermilion 
or indian red. At this stage the growth is in a very 
thin layer and the finely wrinkled film adheres closely 
to the potato, but after a few days the zoogla@a becomes 
coarser and thicker, and the color of its outer portions 
changes to a dull brown. Underneath, however, it is 
still as brilliant as at first. It penetrates every crack 
124 
