AND ANIMAL LIFE. 105 



ously distributed to the different organs, and these 

 proportions will be disturbed according to the 

 exercise or energy of the individual functions in 

 question. 



XCIX. The organs that are late of being deve- 

 loped, when perfectly formed, never cease to make 

 regular demands upon the blood; indeed their of- 

 fice is as constant as that of digestion, till the decay 

 of the natural powers of life, although the pur- 

 pose for which they were intended be not con- 

 summated. If there be any difference between 

 them and other organs, it is that they are sub- 

 ject to occasional and periodical changes, which 

 tend more than any thing I have yet mentioned 

 to give an internal distribution to the blood. 



C. The natural excitation of an internal 

 viscus produces the same local alterations that 

 the morbidly-excited action of any part of the 

 system occasions in the condition of its organiza- 

 tion ; we have in both increased action and a 

 highly vascular appearance ; the striking dissi- 

 milarity between them is in the consequences 

 which succeed. The disorders of the one subside 

 with the cause which gave them rise, but those of 

 the other are followed by febrile symptoms, a 

 derangement of other viscera, and sometimes with 

 disease of its own structure. From this general 

 view of the changes which are peculiar to the 

 animal economy at a certain period of life, it must 

 be obvious to the reflecting mind, that these 



