96 TRANSACTIONS OF THE [MaR. 11, 
medium; again a slight growth may be observed. Culture 3, 
however, grew well, producing a considerable mass of growth of 
a slimy pale pink in 17 days. 
Color.—Practically no variation was observed in the charac- 
teristic pink color of the growth masses of this coccus. There 
seems to be no tendency toward a permanent white form on re- 
peated cultivation. Grown at 374° C., growth is poor and with- 
out color, but the pink tint is regained after the culture has been 
removed to the room temperature. 
Bacittus Lactis ERYTHROGENES (Hueppe). 
Synonymy.*— Bacillus lactis erythrogenes, Hueppe, Fortschr. der 
Med., Vol. VII., p. 141, 1889. 
Bacillus versicolor, Prudden, Proc. N. Y. Pathological Soc., 
1889, p. 103. 
Bacillus helvolus, Zimmermann, Die bak. unser Nutz-u. Trinkw., 
Part I., 52, 1890. 
Occurrence.—(1) Cultures from the collection of the Depart- 
ment of Pathology, Coll. P. & S., of Columbia College. (2) In 
the air in different parts of the college building, 59th st., in the 
yard on 59th st.,ina barn (Dr. Freeman). (3) In the air of my 
flat W. 69th st. (4) In the yard, 59th st., Oct., 1894. (5) Same 
as 4. (6) Same. (7) A culture from Kral, marked “ B. helvo- 
lus.” 
: VARIATION IN BioLoGICAL CHARACTERS. 
Liquefaction of gelatin.—Liquefaction usually begins in from 
3 to 6 days; in about half the cultures in 3 days. In culture 3 
no liquefaction was obtained till 35 days, whena dry hollow was 
observed to have been formed; but on preparing a second cul- 
ture from this tube, liquefaction set in in 15 days, and was well 
marked in 20 days. 
The degree of acidity of the medium has an effect on the 
rapidity of liquefaction, as shown by the following table: (Cul- 
tures all made from the same tube of culture 3.) 
The optimum degree of acidity for this species seems to be 
about .15 cc. of tenth normal sodium hydrate solution acid per ce. 
to phenol-ptalein (distinctly alkaline to litmus). But in another 
instance, where two cultures were made from the same tube 
(culture 1) in two tubes filled with .4 acid gelatin, under the 
same conditions, one did not liquefy for 10 days, while the other 
began to liquefy in 4 days. Perhaps this difference may have 
been due to a difference in the number of bacteria on the innocu- 
lation needle. 
* These names may be used to indicate varieties. ~ 
