190 
HISTOLOGY OF ANIMALS. 
Portion of an injected lobule 
of human adipose tissue. 
fig. 144. 
fig. 143. diameters. This vascular net- 
work can only be demonstrated 
by injected specimens, and the 
arrangement of the vessels 
may be rendered more dis- 
tinct by dissolving out the fat 
by oil of turpentine. When 
large masses of adipose tissue 
are treated in this way, the walls 
of the cells are readily distinguished when viewed 
by transmitted light. In birds, the adipose cells are of 
smaller size than in mammalia, and when injected the 
capillary net-work is closer. Small lobules of adipose 
tissue sometimes surround 
the pulps upon which the 
feathers are formed, and the 
capillaries of these lobules 
very much resemble those 
of some glandular organs, as 
is strikingly exemplified in 
a portion of the skin of a 
young Pigeon , Fig. 144. At 
a and b , are shown the capil- 
laries of two lobules, magni- 
fied forty diameters, and at c, a portion of one of the 
same, magnified two hundred diameters. 
When speaking of the adipose tissue of the Whale, 
I mentioned the receptacles between the fibres for the 
lodgment of the cells ; a' specimen of this tissue would, 
a b, injected lobules of adipose 
tissue from the skin of a Pigeon ; 
c, portion of the same magnified 
200 diameters. 
