FEVERS. 561 



agree with our general doctrine of fevers ; and they are parti- 

 cularly well illustrated by Wintringham, in his Commentarium 

 Nosologicum ; or if there is any doubt with regard to their in- 

 fluence, Sydenham himself, who supposes fevers to arise from 

 miasmata, has given us the fullest proofs of the facts I have 

 mentioned. For though he supposes an epidemic constitution 

 independent of the sensible qualities of the air, he observes that 

 it suffers various modifications according to the states of the 

 weather ; and although this difference will not go so far as he al- 

 leges, yet it is sufficient to establish this point, that the sensible 

 qualities have a share in modifying that state of the air which 

 arises from miasmata and contagion." 



CHAP. V. OF THE PROGNOSIS OF FEVERS. 



" With regard to the event of fevers, this is the fundamental 

 principle : in fevers nature cures the disease ; that is, certain 

 motions tending to death continue the disease, but in consequence 

 of the laws of the animal economy, other motions are excited by 

 these, which have a tendency to remove it." 



XCIX. As fevers (by LX.) consist of both morbid and sa- 

 lutary motions and symptoms, the tendency of the disease to a 

 happy or fatal issue, or the prognostic in fevers, has been es- 

 tablished by marking the prevalence of the morbid or of the sa- 

 lutary symptoms ; and it might be properly so established, if we 

 could certainly distinguish between the one and the other of 

 these kind of symptoms. But the operation of the reaction, or 

 salutary efforts of nature in curing fevers, is still involved in so 

 much obscurity that I cannot explain the several symptoms of 

 it so clearly as to apply them to the establishing prognostics ; 

 and this I think may be done better by marking the morbid 

 symptoms which shew the tendency to death in fevers. 



C. This plan of the prognostics in fevers must proceed upon 

 our knowledge of the causes of death in general, and in fevers 

 more particularly. 



The causes of death in general, are either direct or indirect. 



The first are those which directly attack and destroy the vital 

 principle as lodged in the nervous system ; or destroy the or- 



