BLASTOMYCES 



427 



unstained specimens, and even in stained specimens, they are exhibited 

 with difficulty; in young, resting cells, and by special staining methods. 

 To exhibit the nuclear structures, the yeast cells must first be fixed 

 in picric acid, and after having washed this out they must be stained 

 with Haidenhain's iron-hematoxylin. It has also been shown that 

 the nucleus of the yeast cell divides by a simple karyokinetic or by an 

 (un/totic type when a bud is produced or when the endogenous asco- 



FIG. 173 



Pseudofarcy, or blastomycosis, in a Filippino pony. The picture shows several swollen, 

 subcutaneous lymph nodes and one open ulcer. (Strong.) 



spores are formed. The latter are generally somewhat more resistant, 

 particularly to drying out, than the adult vegetative organism. In 

 addition to the nucleus the vegetative adult organism also often exhibits 

 much more readily seen vacuoles filled with fluid and in old cells 

 highly refractive granules, which consist of proteid material, but also 

 contain some fat. In cover-glass preparations the blastomyces can 

 be stained by the ordinary watery anilin stains; in tissues they are best 



