108 STORRS AGRICULTURAL EXPERIMENT STATION. 
the action upon milk we have always used both the temperature , 
of 20° and 37°. In our descriptions in the following pages we 
have not referred to the action of these two temperatures, except 
in cases where it was different at the two temperatures. It will 
be understood, then, that the actions given as taking place in 
milk occur at both temperatures unless otherwise specified, al- 
though usually, of course, more rapidly at the higher temper- 
ature. The digestion of milk has been determined by eye only. 
We have hitherto done no work upon strictly anaerobic bac- 
teria. Most of the forms which we have described have been 
aerobes, although some grow more readily if they do not have 
too abundant a supply of oxygen. ‘The question of their rela- 
tion to oxygen we have determined from their surface growth 
on various media, their growth in the closed arms of the fer- 
mentation tubes, and also from their growth under a mica plate 
which we have always made and frequently found useful, al- 
though we have not tabulated it in the following pages. 
DETAILED DESCRIPTION OF TYPES. 
A. NON-LIQUEFYING COCCI.—STREPTOCOCCI AND MICROCOCCI. 
I. Types that do not produce acid. 
MM. lactis rosaceus n.s. A pink Micrococcus. This organism, orginally 
found in 1903, has been found twice since, in milk, in this vicinity. All cul- 
tures agree in essential particulars. 
Morphology.—Size, .8uin diameter. Stains by the Gram method. 
Gelatine colony.—Surface colony reaches the size of I mm., with a nucleus 
and a light outer zone. he color is pink. On “tmus gelatine it produces a 
bluish colony which is not acid. 
Gelatine stab.— A needle growth and a spreading pink surface, 
Agar streak.—A luxuriant pink growth. 
Fermentation tubes.—No acid nor gas is produced in any sugar bouillon, and 
no growth in closed arm. 
Bouillon.—A sediment and a slight turbidity, but no pellicle. 
Mitk.—Rendered slightly acid and shows a slight pinkish sediment. It 
becomes somewhat slimy. 
Potato.—A very luxuriant, thick, moist growth of a pink color. 
Grows at both 20° and 37°. Aerobic. 
M, lactis citreus Bon. s. A yellow, non-acid Coccus. (Perhaps= J, citri- 
nus Migula). The similarity of this culture to our yellow liquefying coccus leads 
us to think that they are perhaps the same and hence the use of the same name. 
(See AL. lactis citreus A, p. 118.) This organism has been found but once in 
milk in Middletown. Its characters are as follows: 
Mor phology.—Size, .84. No chains produced. Stains by the Gram method. 
