85 
Starch agar.—This medium proved to be of but slight difterential 
value. The growth was of a dark color and of somewhat bluish tinge. 
Bean agar.—-H. Nos. 1, 3, 5, 13, 20, grew well on bean agar, all de- 
veloping a dense, woolly, gray aerial mycelium. Zonation was poor, or 
obscured by the aerial mycelium. The five strains showed no differences 
in growth on this medium, which was therefore poor for differential use. 
In Freudenreich flasks there was a definite black surface-line and much 
tawny aerial mycelium in clumps. 
Brazil-nut agar.—(Formula according to Spencer, 108.) H. No.1 in 
test-tubes grew very rapidly and luxuriantly with small development of 
aerial mycelium and a distinct black basal line. The agar was rapidly 
cleared of proteid precipitate by the development of a proteolytic enzyme. 
In Petri dishes a thick, dense, woolly, snow-white aerial mycelium devel- 
oped which entirely curtained the surface-blackening. The colony was 
surrounded by a broad translucent zone due to proteolytic action. This 
agar is valuable for the pure-white aerial mycelium that develops on it, 
and to demonstrate readily the proteolytic action, though it did not, 
even in these regards, prove to be differential, since all of fifteen strains 
tested upon it gave nearly identical responses. 
Oat agar.—H. No. 1 at 10 days gave a distinct black surface-line 
and very heavy aerial gray growth. H. Nos. 1, 4, and 14 were indistin- 
guishable on it. 
A pple-fruit agar —H. No. 1 gave a black basal line and abundant, 
sooty aerial mycelium. H. Nos. 1, 4,and 14 were alike except that No. 4 
produced large sclerotia. 
A pple-bark agar.—H. Nos. 1, 4, and 14 grew very slowly and were 
very dense and black, with but little aerial mycelium. 
Czapec agar.—H. No. 1 gave a black surface-line and no aerial my- 
celium. H. Nos. 4 and 14 were of the same character except that No. 4 
produced a considerable quantity of smoky aerial mycelium. 
Prune agar.—H. Nos. 1 and 4 gave a dense, black surface-growth but 
no aerial mycelium. 
SUMMARY CONCERNING GROWTH ON AGARS 
Corn-meal agar made by the usual 60° formula proved most useful, and 
the best differential agar. If made at 100° or at 43° it lacked nutri- 
ment. The amount of agar used—eyven 25 g. per 1000 c.c——had but little 
effect on growth characters. Green-wheat agar in varying strengths led 
to luxuriant vegetation, to little conidia-production, to much abnormality 
