100 
bottom up, and observed carefully, but no difference in rates or characters 
of growth was observed. 
Growtu or H. No. 1 IN THE DARK AND IN THE LIGHT 
Growth of colony-diameter (millimeters) at 
esa near 
Temperature Condition rare Paes ot ite 
2\da. | 3 da. | 4 da. | 5 da. | 6 da. | 7 da. 
? PA 32 44 56 71 85 
25 Dark ai || 38 46 |59 | 74 85 
SORTS 5 981s BODE Ce CS Se CS CeO coat ee DANS NSIS RY ERY Ein a Sherali ritets 
. ¢ 17 34 48 | 61 75 90 
25 Light 19 | 34 48 | 60 | 74 90 
Pare  Emetercenitell cies) ein 'aycce's oo cre Sati ce lel seed or 18 | 34 48 | 60.5 | 74.5} 90 
CARBOHYDRATES 
Brazil-nut agar in Petri dish with H. No. 1 gave snowy white colonies. 
When such colonies had reached a diameter of about 3 cm. one oese of 
powdered dextrin, maltose, rhamnose, or glucose was placed on the agar 
a few millimeters from the advancing edge of the colony. Within 48 hours 
the portion of the colony near the added carbohydrate, with the exception 
of rhamnose, produced conidia in much greater abundance than before, and 
the mycelium turned slightly dark. Starch, corn-oil, and corn-meal pro- 
duced a similar effect, but with delay of nearly 48 hours, suggesting that 
the additional time required was needed for the production and action of 
enzymes, diastase, or lypase, as the case might be. 
Again, plain-agar plates were poured and inoculated with H. No. 1, 
and when the colony was well developed various carbohydrate nutrients 
were laid on the agar near the advancing edge of the colony: steamed rice, 
steamed tapioca, 1 square centimeter of standard corn-meal agar, a frag- 
ment of a Brazil-nut, corn-starch, wheat flour, corn-meal, and buckwheat 
flour. All of these nutrients were used, and in each case the colony in the 
region of these nutrients turned black, owing to the quantity of conidia pro- 
duced (Pl. XVI). Ravn (91) noted a distinct relation between carbohy- 
drate nutrients and blackness in Helminthosporium, as did I in various 
fungi (118). 
On plain agar, glycocoll and aspartic acid inhibited strongly at first, 
but later the fungus grew through these. It grew normally through ty- 
rosine, glutamic acid, leucin, cystine, phenyl, and alanine without percep- 
