Vlll PREFACE. 



ever with the subject treated. For the same rea- 

 son, I have avoided all professional pedantries, all 

 learned technicalities, all crack-jaw words (when it 

 could be done consistently with perspicuity); and I 

 have described just so much, and no more, of the 

 structure of the body as I thought sufficient to give 

 the general reader a clear idea of those parts only 

 which are concerned in the preservation of health. 

 Thus, in speaking of the heart, I have divided it 

 into two cavities a right and a left ; although, in 

 fact, each of those cavities is again divided into two 

 others. But, as a knowledge of this fact is not at 

 all necessary to the understanding the general func- 

 tions of the heart; and, as the description of this 

 second division into cavities would necessarily in- 

 volve a description of mitral, semilunar, and tricus- 

 pid valves, fleshy columns, tendinous cords, cur- 

 tains, &c. all of which would be " caviare to the 

 general"; I have thought it best to confine myself 

 to the first grand division the only one necessary 

 to be known, in order to acquire a lucid notion of 

 the course pursued by the blood. I pretend not 

 herein to teach the anatomical structure of our 

 organs generally; but only to exhibit the several 

 changes necessary to nutrition, which are wrought 

 upon our food within the ULTIMATE TISSUE of 



