DISEASES CAUSED BY MOLDS, ETC 
105 
The protoplasm contains vacuoles and one or more 
nuclei. The manner of reproduction is characteristic; 
the capsule protrudes and forms a bud and contains a 
part of the protoplasm and a half of the nucleus. It 
gradually grows larger, and is eventually pinched off 
to become another cell. The cells frequently contain 
spores, which are liberated when the cell disintegrates. 
The most important property of yeasts is the fer¬ 
mentation of sugars whereby the sugar is changed 
into ethyl alcohol and carbon dioxide. Commercially 
the yeasts are used in a variety of ways, but chiefly 
in the manufacture of beers and wines. Few of the 
yeasts are infectious for man, and but one will be 
mentioned. 
Blastomycosis. 
This infectious disease is caused by a yeast called 
the blastomyces. In appearance it corresponds to the 
yeast-cells described above, having a thick cell-wall, 
with one or more nuclei in the protoplasm, and 
vacuoles. Occasionally it forms threads called mycelia 
(sing, mycelium). 
The skin is most often affected. Small nodules 
form, which soften and discharge a yellow pus. They 
spread slowly and sometimes involve a considerable 
area of skin. Infection of the lungs is more serious 
and often leads to pneumonia. A few cases of gen¬ 
eral infection have been reported with abscesses in 
the liver, spleen, and lungs. 
Where the organisms that cause the disease come 
