PREFACE. vii 



agate others fimilar to themfelves ; which does not uni- 

 formly occur in fuch vegetable productions as are term- 

 ed varieties. 



, In fome other genera of nofologifts the fpecies have 

 no analogy to each other, either in refpect to their prox- 

 imate caufe, or to their proximate effect, though they may 

 be fomewhat fimilar in lefs effential properties ; thus 

 the thin and faline difcharge from the noftriis on going 

 into the cold air of a frofty morning, which is owing to 

 the deficient action of the abforbent veflels of the nof- 

 trils, is one fpecies ; and the vifcid mucus difcharged 

 from the fecerning veflels of the fame membrane, when 

 inflamed, is another fpecies of the fame genus, Catarrhus. 

 Which bear no analogy either in refpect to their imme- 

 diate caufe, or to their immediate effect. 



The ufes of the method here offered to the public, of 

 clafling difeafes according to their proximate caufes, are, 

 firft, more diftinclly to underfland their nature by com- 

 paring their eflential properties. Secondly, to facilitate 

 the knowledge of the methods of cure ; fince in natural 

 claflification of difeafes the fpecies of each genus, and in- 

 deed the genera of each order, a few perhaps excepted, 

 require the fame general medical treatment. And laftly, 

 to difcover the nature and the name of any difeafe previ- 

 oufly unknown to the phyfician ; which I am perfuaded 

 will be more readily and more certainly done by this 

 natural fyftem, than by the artificial clarifications alrea- 

 dy publifhed. 



The 



