158 » CAPILLARY VESSELS. 
lowish-red colour. Notwithstanding repeated endeavours, I 
cannot succeed at this season of the year when the hens are 
moulting, in subjecting eggs to incubation for so long a period, 
I can, therefore, only give a representation of these vessels 
from a recollection of what I observed in the early part of 
this year. (See pl. IV, fig. 12.) In some situations the capil- 
laries are perfect, and connected with the larger vessels ; at 
others they have the appearance represented in the figure, and 
illustrated previously by observations on the tail of the tadpole. 
In addition to these capillaries, which form a network of 
canals of irregular caliber and give off blind branches, some 
separate irregular corpuscles are seen, such as / and 7, which 
do not appear to be connected with the vascular network. 
These bodies send off blind processes of various forms in 
different directions, and have the appearance, therefore, of 
stellate cells. They have a yellowish-red colour, like that of 
the bone-capillaries, which circumstance is alone sufficient to 
suggest the supposition that they are cells of capillary vessels 
in progress of development. This becomes much more pro- 
bable, when we observe some of these corpuscles, such as 4, 
already connected with the true capillaries. We may, there- 
fore, with a high degree of probability at least, regard them 
as the primary cells of capillary vessels; and in that case the 
description of the formation of these vessels, previously given, 
would be the correct one. The following would, therefore, be 
the mode in which the formation of the capillaries and of the 
blood takes place in the germinal membrane: among the 
cells which compose the germinal membrane, some which are 
deposited at certain distances from one another, are deve- 
loped into the primary cells of capillary vessels by becoming 
elongated on different sides so as to form stellate cells. 
The processes of the different cells come imto contact and 
coalesce, the septa are absorbed, and in this manner a network 
of canals of very irregular caliber is produced, the prolonga- 
tions of the primary cells being much thinner than the bodies 
of the cells. These processes of the cells or passages of com- 
munication undergo expansion until they and the bodies of 
the cells all attain one equal width, until, in fact, a network of 
canals of uniform caliber is formed. The fluid portion of the 
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