10 PHYSIOLOGY. 



functions reduced to the two heads of Sense and Motion, 

 be explained in our second section. But it would be improper 

 to enter there on the consideration of the exercises of the parti- 

 cular senses and motions, and therefore we have reserved them 

 for the fifth and sixth sections. 



" Hitherto I have been speaking of the preparation that is 

 necessary to the understanding of certain parts. With regard 

 to the whole, the human body is a machine that must be gov- 

 erned by the laws of matter and motion that affect every part 

 of nature ; and, therefore, to the understanding of it, some 

 of the principles of natural philosophy are very necessary ; and 

 I do not know where gentlemen have a better opportunity of 

 studying these, in the most fundamental manner, than in this 

 university. The knowledge of chemistry, so far as it considers 

 the nature of the body and of the fluids, will be likewise neces- 

 sary ; but especially the knowledge of anatomy must every 

 where accompany our present study ; and I must suppose you 

 all instructed in that respect, for if you are not, it will be im- 

 possible to supply it."" 



SECT. I. 



OF THE SIMPLE SOLIDS. 



VII. The solid parts of the body seem to be of two kinds : 

 one whose properties are the same in the dead as in the living, 

 and the same in the animate as in many inanimate bodies; the 

 other, whose properties appear only in living bodies. In the 

 last, a peculiar organization, or addition, is supposed to take 

 place ; in opposition to which, the first are called the SIMPLE 

 SOLIDS. Of these only, we shall treat here ; and of the others, 

 which may be called VITAL SOLIDS, being the fundamental part 

 of the nervous system, we shall treat under that title in the 

 following section. 



VIII. The simple solids are suited to the purposes of the 

 animal economy by a certain force of cohesion, joined with a 

 certain degree of flexibility and elasticity. 



IX. These properties of the simple solids, in different parts 

 of the body, in different bodies, and on different occasions in the 

 same body, are necessarily in different degrees ; and this seems 



