ATAVISM. Tye 
glands, thus furnishing an excellent example of large 
and numerous skin glands occurring in a_ protected 
situation. ; 
It has long been established that milk-glands are 
modified sebaceous glands, and the difference in the 
Fic. 91.—The inguinal region of a Lamb, showing the cutaneous 
recesses in its groin. 
nature of the secretion is not very great. The sebaceous 
variety furnishes a fatty unctuous substance ; mamme, 
a natural emulsion known as milk, consisting of oil 
globules suspended in fluid, containing various salts and 
a proteid body, casein, with a small but variable propor- 
tion of albumen. 
