238 BACTERIA. 
had found the Micrococcus chlorinus which Cohn ob- 
served on hard-boiled eggs. 
Cultures made from these green dots, developed green 
zoog lope with rod-like cells, which tended to confirm my 
theory. They were slightly larger than the original B. 
chlorinum cells. With these were mingled a few spher- 
ical cells. The new zoogloa had a deep-green color 
with a reddish tinge, as might have been expected. 
Upon one occasion I was kindly supplied by Prof. 
Dwight with. a peculiar preparation of milk called 
youghwort, and much esteemed in Turkey. <A culture 
of this developed several diverse forms of bacteria which 
were so badly mixed that my efforts at isolation were 
unsuccessful. The potatoes became eventually covered 
with a tough formation of a dull salmon color. This 
deserves more extended study than I was able to give. 
Bacillus, species a. <A bacillus producing a white 
zoogloa seems to be rather common here. It was ob- 
served in cultures from the main building, from the 
natural history laboratory, and from the barn. 
As first seen this usually presented a grayish white 
coloration, with sometimes a slight greenish tinge. Many 
cultures were milk-white for a week or two, then be- 
came creamy, and finally brownish in color. The 
zoogloea varies in consistency from that of cream or soft 
lard to a nearly solid state, with a dry, roughish sur- 
face ; in general, it is waxy, and spreads smoothly over 
the cut surface of the potato. ‘ 
In some cultures the cells agreed in size and form 
with those of Bacteriwm candidum, but as the zoogloea 
is never glairy, ropy, powdery, or wrinkled, it cannot by 
any possibility be referred to that species. More com- 
monly the cells are much swollen and vacuolate. These 
occur in chains of several articles, or singly. Associated 
with these I frequently found little oval bodies which I 
122 
