81 



pletely overgrown and of an even black color, largely curtained by an 

 abundant, even overgrowth of white aerial mycelium. At contact with 

 the glass a sharp, black line gave clear evidence of the black surface-coat. 

 No clumps or balls of mycelium were present. At 22 days a few clumps 

 developed, though not so many as on H. Nos. 9, 13-16. 



Cultures of H. No. 1 on corn-meal agar in large flasks, as those of 

 Kolle or of Piorkowski (PL XI-XIII) gave colonies very different from those 

 on the ordinary Petri dish, due presumably to the larger quantity of 

 nutrient available and to different humidity relations. These flasks 

 gave increased density of colony and conidia-formation, more aerial 

 mycelium, and some clumping of the mycelium. Though colonies of H. 

 No. 3 and H. No. 1 differed in these characters in these flasks (PI. XII, 

 XIII), portions of the colonies of these strains were indistinguishable. 



Corn-meal agar made at various temperatures. Corn-meal agar was 

 made in the usual manner excepting that the temperature in three cases 

 was held at 43, 85, and 100 respectively, instead of at 60, before 

 filtering. Duplicate plates were made. The four resulting agars are 

 designated according to the temperatures held, and colony data for each 

 are presented in the following table. 



CORN-MEAL AGAR MADE AT VARIOUS TEMPERATURES 



The 100 agar is most favorable to linear growth, 43 agar stands 

 next; 43 and 85 agars give growth of poorer color than 60 agar, but 

 100 agar ranks lowest in this regard. Color is directly due to quantity 

 of conidia, and it is uniform in the mycelium on the four agars. Nutrition 

 in 100 agar was very little better than in plain agar. In general, it 



