HISTOLOGY OF ANIMALS. 
LECTURE X. 
ANIMAL TISSUES. 
I now proceed to consider the elementary tissues 
of animals, and see how far they correspond with those 
of vegetables. In their earliest condition the cells in 
both are nearly alike, in some cases the cellular 
character is maintained throughout life, but in others 
they rapidly undergo change of form, and all appear- 
ance of cell and nucleus is entirely lost. The animal 
cell, though in some degree possessing an independent 
existence, cannot perform its functions, as for example, 
that of secretion, without being in a certain relationship 
with a series of vessels carrying the nutritive fluid or 
blood. In the Animal as well as in the Vegetable 
Kingdom, we have membrane as an element ; it may 
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