PARASITOLOGY. 79 



cyst by migration, and if they reach the bronchi may 

 be expelled with mucus through fits of coughing, and 

 thus soil the feed or water. In the adult state the 

 parasites infest the nasal chamber, and possibly the 

 pharynx and larynx. They hold on to the mucous 

 membrane by means of booklets and produce an 

 inflammation which is accompanied by a muco-puru- 

 lent discharge. The animal sneezes, scratches and 

 rubs its nose, etc. 



FUNGI. 



The fungi that attack animals are vegetable para- 

 sites and are similar to the common moulds in their 

 general appearance and method of reproduction. 

 Reproduction is by spores, which are small round 

 bodies, microscopic in size, resembling small seeds. 

 The filaments, or hyphae, consist of a series of cells 

 arranged end to end. These cells consist of a cell 

 wall and protoplasm. The spores have a greater 

 resistance to unfavorable conditions than the mycelia, 

 and when placed under favorable conditions, or **fer- 

 tile ground," produce the hyphae. 



Trichophyton Tonsurans (Trix — hair ; phyton, a plant.) 



(Tonsurans — to shear.) 



Disease. — Tinea tonsurans: circinate ringworm; 

 ringworm. 



Animals hifested. — Man, horse, ox, hog, dog, cat, 

 sheep, and bird. 



Syniptonis. — The affected spot is at first red; it 

 gradually enlarges and is covered with a thin, gray- 

 ish scale, under which is found serum. The hair is 

 cut off at the surface as a result of the invasion of 

 the skin by the fungi. The circumference is red. 



