vi PREFACE. 



In the fubfequent clarification of difeafes I have not 

 adhered to the methods of any of thofe who have pre- 

 ceded me ; the principal of whom are the great names 

 of Sauvages and Cullen ; but have neverthelefs availed 

 myfelf, as much as I could , of their definitions and dif~ 

 tinctions. 



The effential characteristic of a difeafe confifts in its 

 proximate caufe, as is well obferved by doctor Cullen, 

 in his Nofologia Methodica, T. ii. Prolegom. p. xxix. 

 Shnilitudo quidem morborum in fimilimdine caufse 

 eorum proximse, qualifctinque fit, revera confiftit. I 

 have taken the proximate caufe for the claffic character. 

 The characters of the orders are taken from the excefs, 

 or. deficiency, or retrograde action, or other properties, 

 of the proximate caufe. The genus is generally derived 

 from the proximate effect. And the fpecies generally 

 from the locality of the difeafe in the fyfhem. 



Many fpecies in this fyftem are termed genera in the 

 fy Items of other writers ; and the fpecies of thofe wri- 

 ters, are, in confequence, here termed varieties. Thus, 

 in Dr. Cullen's Nofologia, the variola or fmall-pox is 

 termed a genus, and the diftinct and confluent kinds are 

 termed fpecies. But as the infection from the diftinct 

 kind frequently produces the confluent kind, and that of 

 the confluent kind frequently produces the diftinct ; it 

 would feem more analogous to botanical arrangement, 

 which thefe nofologifts profefs to imitate, to call the dif- 

 tinct and confluent fmall-pox varieties than fpecies. 

 Becaufe the fpecies of plants in Botanical fyftems prop- 



agate 



