in their relation to the Seasons. 243 



seasons were regular. It is, however, certain, especially with 

 us, that this supposition constitutes the rarest cases : our sea- 

 sons vary very frequently, both in their characters and rela- 

 tions. 



To know completely the pathological action of the seasons, 

 it is necessary, then, to consider both the ordinary atmospheric 

 phenomena, and those which are unusual, or the intempera- 

 tures and the modifications which proceed from the influence 

 of each locality. 



Certain special physiological determinations ; certain pro- 

 found organic modifications ; certain distinct general diseases 

 correspond, under certain conditions, to the action of the dif- 

 ferent seasons. These common maladies of the year are ge- 

 nerally divided into two classes ; one of these comprehends the 

 diseases of the regular course of the weather : these are the 

 medical constitutions of the seasons : the other includes the 

 diseases of the irregular weather. 



These two classes of diseases resemble each other in many 

 points : they acknowledge the same causes ; they affect the 

 same masses ; they are developed and grow by degrees ; they 

 vary much in their forms, but very little or not at all in their 

 nature or essential characters. 



During regular seasons, and under temperate climates, enjoy- 

 ing the four seasons, the prevailing morbid states, at the be- 

 ginning and end, unite or combine with the morbid state of 

 the neighbouring season ; so that, at the transitions of each 

 season, one observes a mixed, complex, pathological state, re- 

 sulting from the concurrence of the action of the season which 

 ends, and that of the season which commences. Therapeutics, 

 we may observe in passing, profit much by the sagacious deter- 

 mination of these delicate variations, in perfect correspondence 

 with the facts very frequently remarked by attentive observers. 

 Neither the regular seasons nor the iiTegularities of the 

 weather necessarily engender the afifections which are corre- 

 lative to them ; they only produce these diseases when the 

 living body, by a predisposition, oftener observed than deter- 

 mined, but which a well directed study of the temperaments 

 allows to presume, is rendered sufficiently accessible to their 

 impressions. What is certain is, that the wise precepts of the 



