6 PHYSIOLOGY. 



ology referred to the conditions of the mind, as well as to those 

 of the corporeal part. So far from being able to neglect the 

 mind, the most considerable functions are connected with par- 

 ticular operations, and a particular state of our immaterial part; 

 and, indeed, I find that the conditions of the human mind must 

 engage our attention more than they have done hitherto. Some, 

 indeed, have thought that I have gone too far in introducing a 

 great deal of metaphysics into my course ; but unless the his- 

 tory of the operations of the human mind is to be considered as 

 such, they are mistaken ; and I resolve to go no further than 

 I can point out these operations as referring to the state of the 

 body." 



V. The functions of the animal economy are many and vari- 

 ous, and so complicated with each other, that it is difficult to 

 find the most proper order in which they may be delivered. 

 " By looking into the works of physiologists, you will see abun- 

 dant proofs of this, and it will be easy to find out the reason of 

 it : The functions are complicated, and mutually dependent 

 upon one another. Many of the functions may be considered 

 as mutually the causes and effects of each other. Thus, the 

 action of the heart cannot subsist without the power and energy 

 of the brain ; nor can the energy of the brain subsist long with- 

 out the action of the heart." That, however, seems the best, 

 which considers them, as nearly as may be, according to the se- 

 ries of causes and effects. " I say that, as nearly as is possi- 

 ble, that organ and function should be considered first, the 

 knowledge of which is necessary to understand what is to come 

 after. We should take the several matters with some view to 

 their dependence on one another, and should suppose nothing 

 known that has not been previously explained. I say as nearly 

 as possible, for it is impossible to do this entirely." 



VI. Upon this plan we shall treat 



1. Of the solid matter, of which a great part of every organ 

 of the body consists. "We cannot consider a function without 

 considering its organ ; and we cannot consider a single organ 

 without considering in general the solid matter of which it is 

 formed. 



" The most remarkable organs are the muscular parts. A 

 very small acquaintance with the body shews that there is hard- 



