56 UNIVERSITY OF WISCONSIN STUDIES 
For the work with molds an agar containing the nutrient salts, 
potato broth, and cane sugar gives excellent growths, although 
ordinary nutrient agar serves nearly as well. 
For obtaining the spores it is well to use a culture a month 
or two old. Controls were always employed to determine 
whether the inoculations were successful. Two controls, one 
made at the beginning and the other one at the end of the ex- 
periment, were sometimes made but this is scarcely necessary 
for mold spores possess a remarkable resistance against desicca- 
tion. 
CuLtTuRES UsEp 
Representatives of the more common molds were employed 
in the trials. A black mold of as yet undetermined species 
represented the Mucoraceae; Aspergillus niger, Aspergil- 
lus fumigatus, Aspergillus nidulans, Oidium lactis and 
Penicillium glaucwim were the other forms used. All the 
forms are exceedingly common and were obtained from the 
air or from decayed fruits, excepting the Otdiwm which was 
isolated from milk. Aspergillus fuinigatus was included be- 
cause of its pathogenic powers for animals. 
The following tables present the results when the spores 
of these molds were exposed to direct sunlight. 
‘TABLE I.—MUCOR SP. 
| Time Exposed (hours) 
Date | Age of Culture 
Growth No growth 
Mareh 27, 1915. Se ee a ae ee Diy Shy Be 
JUDE 285. OIG, we ws wendy seats Taye 107. ** 2, 4, 6G, 10 
