Vlll PREFACE. 



From the rapid sale of the first edition, and the nu- 

 merous orders for the work from all parts of the United 

 States, it may safely be concluded, that Physiology is 

 henceforth to be one of the common branches of know- 

 ledge taught in our schools, academies, and other semi- 

 naries of learning. Indeed it is remarkable, that 

 sciences, so closely connected with the health and hap- 

 piness of our race, as those which teach us the structure 

 and functions of the human body, should so long have 

 been confined to those who intend to pursue the 

 practice of medicine and surgery as a profession, espe- 

 cially when the practical application of such knowledge 

 is daily and hourly of the utmost importance to every 

 individual, connected as it is, with the preservation of 

 health and of life. That such studies are not above the 

 comprehension of children I can testify, not only from 

 my own observation, but from the experience of numer- 

 ous teachers, such as those whose names are appended 

 to the testimonials, on the first pages of this work. If 

 this is not sufficient, I have to commend to the attention 

 of the reader, the following extract from a lecture of 

 Mr. George Combe, the distinguished phrenologist of 

 Edinburgh, which he was so kind as to communicate to 

 me by letter : 



" I take the liberty to urge very earnestly on your at- 

 tention, not only the advantage, but the necessity of in- 

 troducing instruction in anatomy and physiology into 

 popular education. The great laws of health cannot be 

 understood, nor can their importance be appreciated 



