214 PHYSIOLOGY. 



CCCII. The unavoidable death of old persons is thus, in 

 part, accounted for ; but it is, however, still probable, that the 

 same event proceeds chiefly from the decay and total extinction 

 of the excitement or vital power (C XXX VI.) of the nervous 

 system, and that from causes very much independent of the 

 circulation of the blood, and arising in the nervous system it- 

 self, in consequence of the progress of life. This seems to be 

 proved by the decay of sense, memory, intellect, and irritabi- 

 lity, which constantly takes place, as life advances beyond a 

 certain period. / 



OF TEMPERAMENTS. 



(Extracted from the Treatise of the Materia Medica.) 



IN attending to the great number of circumstances in which 

 the bodies of men may be different from one another, it is 

 scarcely possible to enumerate every particular ; but it has been 

 at all times presumed, that a great number of these circum- 

 stances are commonly combined together in the same person ; 

 and that frequently one man shows a combination of circum- 

 stances not only different, but sometimes of an opposite kind 

 to that of another. Such combinations, upon a particular 

 supposition with respect to their causes, the ancients named 

 temperaments , and the term has continued to be employed in 

 the schools of physic from the most ancient to the present 

 time. 



Abstracting from all theory, we continue to employ the 

 same term to denote a combination or concurrence of circum- 

 stances which happens in certain persons, but which in several 

 respects is different from the combination that happens in cer- 

 tain others. Upon this footing, I believe the ancients dis- 

 tinguished what they called the different temperaments of men : 

 for it is probable that at first they distinguished them by actual 

 observation ; but very soon they formed a theory with regard 

 to them, from whence they formed appellations which have 

 continued to be applied to them ever since. The appellations 

 indeed have been continued, though the theories which laid the 



