New YorK AGRICULTURAL EXPERIMENT STATION. 115 
but unfortunately the variation in the results obtained from 
its use is wider than in a majority of the media ordinarily 
employed. Jones and Townsend found this medium well 
suited to the forms which they studied earlier, but the use of 
this medium in the later study at the Vermont laboratory’ 
did not result in any visible growth. <A test of the entire 
collection of cultures at the New York laboratory in 1909 
likewise failed to produce growth in any case. A study of 
the commercially pure chemicals which had been obtained 
from one of the most responsible houses revealed the fact that 
the compound supposed to be di-basic potassium phosphate 
was really the mono-basic salt. This produced a marked 
acidity in the medium and probably inhibited the growth. 
A redetermination with chemicals which were true to name 
gave an abundant growth in all cases. 
Gelatin liquefaction. All of the cultures in this collection 
produced an evident liquefaction in gelatin stab in all of the 
many tests except in the case of one series of cultures made 
at the New York laboratory in 1905, when the entire collection 
either liquefied very slowly or entirely failed to do so. Shortly 
before this date some attention was being given in Europe 
to the suggestion of van’t Hoff?! of the addition of formalin 
to gelatin to raise its melting point. The gelatin used in 
the above tests was of the ** Gold Label” quality and had been 
imported through the regular channels. A discussion of this 
difficulty in the matter of liquefaction before the Society of 
American Bacteriologists at their Philadelphia meeting brought 
out the fact that a number of other workers had had similar 
experiences. With the substitution of a new supply of gelatin 
all of the soft-rot cultures again produced liquefaction. 
While all of these cultures produced an evident liquefaction 
of gelatin the rate at which this result was produced varied 
widely both among the different cultures tested at the same 
time and among the different tests of a single culture. The 
cultures known as Cornell I and Cornell V were isolated on 
4tvan’t Hoff, H. J. Erhéhung des Schmelzpunktes der Nihrgelatin mittels 
Formalin. Centbl: Bakt. u. Par., I, 30; 368. 1901. 
