396 

 PAKT IV. 



MATERIA MEDICA AND rilARMACOPCEIA. 



INTRODUCTION. 



The following portion of the work consists of a Materia 

 jMedi(:;a, that is, a description of the various articles or drugs 

 employed in medicine, especially such as are used in veterinary 

 practice; and a Pharmacopceia, or directions for compounding 

 or mixing them, with occasional observations on the diseases for 

 which tliey are usually prescribed. 



In some former editions the Pharmacopoeia and Materia 

 Medica formed two distinct parts ; in the present they are in- 

 corporated ; that is, the medicinal article or drug, the class to 

 which it belongs, and the fornmla or receipts, are arranged in 

 the same alphabet. This plan appeared to the author more con- 

 venient than that originally adopted. Some readers will jjcrhaps 

 object to the number and variety of the formula, as well as to 

 the number of ingredients which some of them contain ; Ijut, 

 however desirable simplicity may be in medicinal composition, 

 there is, perhaps, a limit which it would be dangerous to p-.iss. 

 On tills subject. Dr. Paris, in his Pharmacologia, makes the fol- 

 lowing remark : " I have already observed that all extravagant 

 systems tend, in the course of time, to introduce practices of an 

 opposite kind : this truth finds a powerful illustration in the 

 history of medicinal combination ; and it becomes a serious 

 question, whether the disgust so justly excited by the polj/phar-^ 

 viacy of our predecessors may not have induced the physician of 

 the present day to cari'y his ideas of simplicity too far, so as to 

 nen-lect and lose the advantages, which in many cases, beyond all 

 doubt, may be obtained by scientific combination." "I think," 

 says Dr. Powel, " it may be asserted, without fear of contradic- 

 tion, that no medicine compounded of five or six simple articles 

 has hitherto had its powers examined in a rational manner." 

 Dr. Fordyce first demonstrated the existence of the singular and 

 important law, that a combination of similar remedies will pro- 

 duce a more certain, speedy, and considerable effect, than an 

 equivalent dose of any single one; thus cathartics not only 

 acquire a very great increase of power by combination with each 

 other, l)ut they are at the same time rendered less Irritating in 

 their operation. The same observation is applied to other 



