60 MICROBES, FERMENTS, AND MOULDS. 
in the horny layer of the epidermis, on which it 
produces a roughness in the form’ of dusty pellicles. 
It “penetrates the hair-follicles, but not deeply, and 
only in the vicinity of the point at which they emerge. 
The.spores of which it entirely consists are generally 
of an elongated form, and give off buds. 
According to Mallassez, this fungus is the prin- 
cipal cause of alopecia; that is, the shedding of 
@o0o9oe 
o oe b 
8&6 
88 gd 
Fig. 32.—Epidermic cell of skin Fig. 33.—Isolated spores, taken 
covered with hair, affected by from pellicles of Pityriasis 
Pityriasis simplex, and covered capitis simplex: a, full spores; 
with spores (xX 1000 diam.). b, empty spores ; ¢, full spores 
budding; d, the same empty 
(x 1000 diam.) 
hair, and the baldness which eventually ensues from 
it. It acts in two ways: (1) its presence and multi- 
plication disintegrate the epithelial layers; (2) the 
foreign body irritates the epidermis, producing exces- 
sive activity in the evolution of cells, and consequently 
the incessant desquamation which is the most apparent 
symptom of the disease. . The shedding of hair is chiefly 
due to obstruction in that portion of the’ hair-follicle 
which underlies the orifice of the sebaceous glands; and 
