168 Revort oF DEPARTMENT OF BACTERIOLOGY OF THE 
Age Amount 
Culture No. when Reaction of 
tested. Precipitate. 
| ead ion aria ae eas CR i ee 3 days —2.2% 0.495 g. 
ay ee Pam eset sn Gy ass aE Ve ed EUR lo Ml ae eg —1.0% 0.460 “ 
SA: ORE vec ce On ate Ora —0.9% 0.474 
a) SOREL eRe) whe eae PLE es eer eae Le neutral 0.445 “ 
Like solutions (5 per ct.) of these precipitates tested on 
carrot sections showed all to contain the enzym, the activity 
of the solution increasing with the age of the culture. There 
was distinctly more in 2 than 1; the difference between 3 and 2 
was very slight and that between 4 and 3 not great. Another 
Similar series of cultures of ages four, six, nine and eighteen 
days respectively showed practically like enzym activities. 
The amount of enzym here, as in the trials with broths of dif- 
ferent composition, seemed directly proportioned to the amount 
of growth. In carrot broths the growth is slower in starting 
than in beef broth and persists in its increase for a longer 
time. This slower start in comparison with beef broth is very 
likely due to the excess of organic acids present in the vegetable 
broth and to the further increase in acidity during the early 
development before the soluble carbohydrates are used up. In 
the neutral beef broth this inhibiting influence is not present 
and the bacterial development is at its height in about four or 
five days, as judged by the degree of cloudiness of the broth. 
Here, as in the preceding trials, there is no evidence that the 
enzym formation is a starvation phenomenon, but rather the 
reverse—viz., the more vigorous development is accompanied by 
more enzym production. Moreover, the enzym after its excre- 
tion into the broth appears to be a fairly stable compound, 
hence tends to accumulate with the age of the culture. 'R. E. 
Smith (1902) develops a theory of the parasitism of Botrytis 
cinerea somewhat at variance with Ward’s idea that the enzym 
development is a starvation phenomenon, and more in accord 
with our own observations on this bacillus. Smith’s conclusion 
is that the fungus in the absence of abundant food cannot 
develop the wall-dissolving enzym. It can, however, develop 
a toxin which kills the host tissues. He regards the initial 
penetration of the host tissues by spore tubes following this as 
