SA ecu A ROM YCETES 
625 
the more slowly developing Blastomycetes. It is necessary to dilute 
material containing the organisms with sterile salt solution or broth 
and to crush the tissue into minute fragments. Once pure colonies 
are obtained, their perpetuation by subculturing is readily accom- 
plished. Slightly acid maltose agar, according to Ricketts,^ is an 
excellent medium both for isolation and subsequent cultivation. The 
colonies upon solid media are at first small, white, elevated plaques 
which later become gray or brownish. After a few days the growth 
becomes wrinkled and the mycelial threads and aerial hyphtv develop, 
which gives the culture a moldy appearance. The hypha^ fill the 
tube around the colony. In fluid media the growth at first is a floc- 
culent mass which collects at the bottom of the tube; a membrane 
or pellicle usually develops on the surface of the medium, falls to the 
bottom, and a new membrane forms. A moderate growth develops 
in gelatin, but the medium is not liquefied. A slight acidity, but no 
other visible change, develops in milk cultures. 
Fig. 96. — Blastomj'ces, maltose broth culture. 
The organism is strongly aerobic and grows at room or body tem- 
perature. At the lower temperature hyphse are more freely formed; 
at the higher temperature the typical budding predominates and few 
or no hypha? appear until after several days' incubation. Freezing 
does not kill Blastomycetes, but an exposure to 60° C. for five minutes 
is fatal to them. 
Products of Growth.— The fermentation reactions are variable. 
Some strains fail to ferment glucose or maltose, while others produce 
gas (CO2) in this medium. On the whole, the fermentative powers 
of the Blastomycetes are much less vigorous than those of the sapro- 
phytic yeasts. Toxins and enzymes have not been detected in cultures 
of the organisms." 
1 Jour. Med. Rea., 1901, 6. .377. 
2 Gutierrez: Quart. Bull. Northwestern Univ. Med. School, 1910, 12, 72 
40 
