184 STORRS AGRICULTURAL EXPERIMENT STATION. 
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venture to determine at present. We think the best course to pursue is to 
recognize the two as different, and we have consequently done so in our 
classification. : 
The following classification is based upon the work of Harrison and Gruber, 
with the aid of such additional data as we have ourselves obtained. 
BACT, AEROGENES TYPE, 
This organism has appeared in literature under a long list of names. The 
organisms of the following list appear to be identical with each other and are of 
this type. 28. pyogenes (Albarran), Bact. aceticum (Baginsky), Bact. theloideum 
(Gassner), Bact. udiguitous (Jordan), Bact. candicans (Frankland), Bact. zur- 
nianum (List), B. capsulatus (Smith), B. chologens (Stern), B. acidi laevolacticé 
(Kozai). It is by no means certain that these organisms are identical, but the 
descriptions given of them agree so closely as to lead to the conclusion that 
they are essentially the same. The general characters of this type are as 
follows: 
Bact. lactis aerogenes (Esch.). The non-motile, acid, gas producers. 
Morphology.—Size, 1.4u-5@x I¢-1.5¢. There are no chains, no spores, and 
no flagella. A capsule is frequently found and the Gram stain is variable. 
Gelatine colony.—Large colonies, 2 mm. in diameter, thick, round, smooth, 
moist, sometimes viscous. On Atmus gelatine they are essentially the same, 
and very strongly acid. They frequently show bubbles of gas under the sur- 
face of the gelatine. 
Gelatine stab.—A good needle growth, and a thick white surface. If sugar 
is present, gas bubbles may appear. 
Agar streak,—Luxuriant, moist, gray-white, smooth. 
Fermentation tubes.—All sugar bouillons show acidity, closed arm growth, 
and an abundance of gas. 
Bouillion.—A turbidity and a sediment, and commonly a pellicle. 
Milk.—Becomes strongly acid, and curdles, bubbles of gas being commonly 
evident. This curd is usually very different in appearance from that produced 
by Bact. lactic acidi. 
Potato.—Luxuriant, of a dirty-white to straw color. 
Grows at both 20° and 37°, but better at 37°. Aerobic. Indol is not 
produced. 
Twenty-three of Harrison's organisms belong to this general type, and we 
have ourselves found it extremely common. 
Among the varieties of this typical form which appear among the many 
cultures studied, we make special reference to the following: 
Variety A.—Produces indol. Among the different cultures belonging here 
some produce the typical thick, aerogenes colony, and some the thinner um- 
bonate colony with a smooth center. 
Variety B, Produces no indol, but has a thick colony more like that of coli. 
Among them are some which produce no acidity in saccharose, and do not 
curdle milk, and others that ferment all of the ordinarily used sugars. 
