Daw BACTERIA. 
stated, the growth of the pink zooglea was very rapid 
and very luxuriant ; the orange-colored, on the contrary, 
developed slowly and never spread over a large surface. 
Its cells, too, were smaller, so that I now regard the two 
forms as distinct species. The orange-colored form may 
possibly be the JZ. prodigiosus, but the pink certainly 
is not. It does not develop the form compared to fish 
spawn which is described as belonging to Colin’s species, 
and it does penetrate the substance of the potatoe, 
while the UZ. prodigiosus is a surface growth. 
The cells are spherical, or more frequently oval, and 
sometimes considerably elongated. The shorter di- 
ameter is about the same asin JZ. prodigiosus, the larger 
varies from .7-1.5 . 
Micrococcus prodigiosus, Cohn. One of my cultures of 
Bacterium chlorinum was attacked by a bright blood- 
red or carmine-colored zooglcea, which for a long time 
puzzled me greatly, as in connection with it I found 
cells of various descriptions. Micrococcoid cells were 
mingled with those of bacteria and bacilli in hopeless 
confusion. I took the utmost precaution to obtain pure 
cultures, but never succeeded entirely. The rod-like | 
cells were evidently impurities. This red growth was 
sometimes covered with a wrinkled film, and sometimes 
presented a smooth, shining surface. 
I have since made several cultures of JZ. prodigio- 
sus from material kindly given by Prof. Farlow and 
others. The size and form of these cells, as well as the 
color and texture of the zooglea when compared with 
my red cultures, were so evidently the same that I think 
there is no doubt that this red growth belonged to the 
Micrococcus prodigiosus. 
At one time the cylindrical cells in my cultures were 
beset on all sides by Httle spherical granules, which I 
thought perhaps belonged to a parasitic Micrococcus, 
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