IV PREFACE. 



object ; and are consequently apt to overlook the 

 indirect but substantial aid which an acquaintance 

 with the laws of health is calculated to afford in re- 

 storing the sick, as well as in preserving the healthy 

 from disease. 



It is true, that almost every medical man, sooner 

 or later, works out this knowledge for himself ; but, 

 in general, he attains it later than he ought to do, 

 and seldom so completely as he would have done 

 had it been made a part of his elementary education, 

 to which he saw others attach importance. In my 

 own instance, it was only when entering upon prac- 

 tice that I had first occasion to feel and to observe 

 the evils arising from the ignorance which prevails 

 in society in regard to it. Impressed afterward 

 more deeply than ever with the interest and utility of 

 the study, I contributed two or three articles on the 

 subject to one of our periodical journals, and re- 

 solved to make them the basis, at some future time, 

 of a more detailed and connected exposition. This 

 I have now attempted ; and, if the result prove use- 

 ful, in any degree, to the general reader or profes- 

 sional student, my object will be attained. The 

 volume being of a purely elementary character, and 

 admitted truths of a useful kind being, in every in- 

 stance, preferred to novelty or ingenious specula- 

 tion, the experienced practitioner will meet with lit- 

 tle to interest him in the perusal ; but for him it was 

 never intended. 



There is a tendency in the minds of many, when 

 a new subject is presented to them, to run away 

 with a part of a proposition* or with an individual 



