H^MORRHAGIKS. 219 



in a plethoric state of the body disposing to haemorrhagy, are 

 always admissible and proper. Here, however, it is to be ob- 

 served, that some choice in the mode of exercise is necessary, 

 and that it should be different according to the particular deter- 

 minations which may happen to prevail in the system. In gen- 

 eral, in the case of plethora disposing to haemorrhagy, bodily 

 exercise will always be hazardous, and gestation more commonly 

 safe. 



" Upon the whole, it is obvious, that exercise promotes the ex- 

 cretions in general, but most especially the external secretions, the 

 perspiration. Now, I would maintain, that even the balance 

 which is kept up by the ordinary secretions, to prevent plethora 

 in general, is, during the course of the cold season, more liable 

 to admit of an internal determination, and so to occasion a ple- 

 thoric state ; and the support of perspiration, which is the es- 

 pecial effect of exercise, is the most active means of preventing 

 the accumulation of blood in these parts. 



" Every motion of the body, whether by its own force or by 

 other powers, does effect this ; but it is what we properly call 

 bodily exercise, that motion which is executed by the body's 

 own internal power, which has the peculiar effect. Let no in- 

 dolent luxurious man therefore think that he will obtain the 

 purpose of obviating plethora by rolling in his chariot. He 

 must take to somewhat more active, such as riding ; but to pro- 

 cure health he must especially have recourse to bodily labour ; 

 because it is a rule, that whatever bodily exercise be employed, 

 it must not be violent, and by fits only : this does not answer 

 the purpose. In proportion as the secretions are forced, they 

 again subside ; so that afterwards the perspiration is diminished 

 as much below its natural standard as it was increased beyond 

 it before; and we cannot therefore recommend the exercise, 

 which folly and amusement induce, which is violent for the time, 

 and not lasting, and allows the perspiration to subside. The 

 exercise which is useful must be moderate, but pretty con- 

 stant, at least more or less steady, according to the necessity 

 or habit of the system. To one man three hours of moderate 

 exercise may be sufficient, whilst another may require six or 

 ten. 



" A curious difficulty occurs with regard to exercise, when 



