PEEFACE. 



IN accordance with the wishes of some influential friends, 

 I have prepared this abridged edition of my text book. The 

 abridgment has been effected by omitting all the histological 

 matter, and all discussions of a too theoretical nature. Other- 

 wise, beyond such changes as the advance of science seems to 

 call for, the text which is left is the same as in the full 

 edition. 



M. FOSTER. 

 SEPTEMBER, 1894. 



