PREFACE. 



X HE Materia Medic a includes all thofe fubftan- 

 ces, which may contribute to the reftoration of health. 

 Thefe may be conveniently diftributed under feven ar- 

 ticles according to the diverfity of their operations. 



i. Nutrientia, or thofe things which preferve 

 in their natural ftate the due exertions of all the irrita- 

 tive motions. 



2. Incitantia, or thofe things which increafe the 

 exertions of all the irritative motions. 



3. Secernentia, or thofe things which increafe 

 the irritative motions, which conftitute fecretion. 



4. Sorbentia, or thofe things which increafe the 

 irritative motions, which conftitute abforption. 



5. Invertentia, or thofe things which invert the 

 natural order of the fucceflive irritative motions. 



6. Revert entia, or thofe things which reftore 

 the natural order of the inverted irritative motions. 



7. Torpentia, 



