[Vor. 8 
34 ANNALS OF THE MISSOURI BOTANICAL GARDEN 
these salts, a second series was arranged with a culture interval 
of 4 weeks. The culture vessels and the quantities of solution 
were as in the preceding series. 
The decoction alone seems not only to afford sufficient nitro- 
gen, but with the exception of P7 the addition of these compounds 
results in decreased growth. 
Proteases—Experiments were conducted in the usual way 
using various substrates. As a source of the enzymes mycelial 
extracts were used in some cases, while in the others the growing 
fungus was employed. 
Action on gelatin.—A 10 per cent solution of gelatin was made 
up in potato decoction, and about 10-cc. quantities of the solu- 
tion were placed in test-tubes. The tubes were then immediately 
autoclaved and slanted. After hardening of the gelatin inocu- 
lation was made. 
TABLE XXIII 
ACTION OF EXTRACTS OF THE STRAINS ON FIBRIN 
Fresh Fresh Fresh Boiled 
Substance added Water n/10 HCl . 5NasCos .5Na:CO; 
Fungus, all strains + E P — 
All the fungi grew fairly well on this medium, showing no 
apparent difference in each strain, and after two weeks all the 
cultures showed liquefaction of the gelatin. Positive qualita- 
tive results were also obtained by using mycelial extracts of all 
the strains. 
Action on fibrin.—The action on this substrate was determined 
by placing in each tube 5 cc. of the fresh or boiled extract, a 
piece of fibrin, also 5 cc. of water, acid, or alkali, and then in- 
eubating. The behavior of all strains was positive except in 
the presence of alkali or where the boiled enzyme was used, so 
that the result may be expressed in a tabulated summary, as in 
table xxii. 
Action on albumen.—Two per cent of egg albumen was added 
to a modified Richards’ mineral nutrient solution containing 
