116 Report or DEPARTMENT OF BACTERIOLOGY OF THE 
practically the same date from diseased turnips in the same 
field and the qualitative record of these cultures in the above 
table is identical in all particulars. They were as similar as 
two subcultures from a single source would be expected to 
be except in the matter of liquefaction. In parallel cultures 
made in triplicate at the same time, on gelatin stabs from the 
same flask of gelatin, from agar slopes treated as nearly alike 
as possible Cornell I produced large dry pits while Cornell V 
liquefied practically the entire stabs in three weeks. Again 
in his description of B. aroideae, Townsend called attention 
to the rapidity of its action, completing the liquefaction in 
3—5 days. In our studies the culture which he furnished us 
varied relatively from one of the more rapid to one of the 
slowest in the collection. The rate and form of liquefaction 
appears to vary with what may be termed the general vigor 
of the culture and more especially with regard to the relation 
of the culture to oxygen. Unfortunately our knowledge of the 
factors which influence the cultures in these particulars is 
extremely fragmentary. 
Miik—Acid Curd. The distinction between acid and rennet 
curds is of historical rather than practical value in the study 
of many bacterial forms. In this group the distinction cannot 
be made with certainty and different observers have varied 
accordingly. The formation of the curd is probably due to 
the joint action of an enzym and of acid. The record was 
made of acid curd -| because there is an evident acid forma- 
tion preceding the curdling. 
Casein peptonized. Here again the various observers dif- 
fered markedly in their conclusions because the visible diges- 
tion of the curd is so slight that it cannot with certainty be 
differentiated from the shrinking which would result from 
the action of the acid on the curd. The action of the various 
cultures on milk was alike and the final record of + was based 
on the results of milk agar plates prepared after the sugges- 
tion of Hastings*? where the ability of the organisms to attack 
the. casein seems to be clearly brought out. 
“Hastings, E. G. Milchagar als Medium zur Demonstration der Erzeug- 
ung proteolytischer Enzyme. Centbl. Bakt. u. Par., II, 10: 384. 1902, 
