FROM THE 



P E E F A C E 



TO 



THE FIRST EDITION 



THE composition of such a Treatise as the following was a part of the 

 original plan of the Author when he first came before the Public as a 

 writer on Physiology. Being desirous, however, of making his first essay 

 in the path which had been previously the most incompletely explored, 

 he deemed it better to await the verdict upon this before proceeding 

 further ; and he was not without hope, that some Writer, more fully com- 

 petent to the task, might in the meantime take up the subject of Human 

 Physiology in such a way as to leave nothing for the Student to desire. 

 This, however, has not been accomplished. The previously existing 

 Treatises upon it, which have been every year becoming more antiquated, 

 have not been replaced by any works, that can be considered as at the 

 same time sufficiently elevated in their character, to represent the present 

 condition of Physiological Science, sufficiently compendious in their 

 bulk for the limited time at the disposal of most Students, and suffi- 

 ciently practical in their tendency to lead their readers to the useful 

 applications of the facts and principles they place before them. This is 

 not the opinion of the Author alone, but that of numerous experienced 

 Teachers throughout the country ; and he has been led to regard the 

 present as a good time for carrying his purpose into execution. 



The plan and objects of his Treatise may be gathered from the pre- 

 ceding statement of the reasons which have occasioned its production. 

 In this, as in his previous work, it has been his object to place the 

 Reader in the possession of the highest principles, that can be regarded 

 as firmly established, in each department of the Science; and to explain 

 and illustrate these, by the introduction of as many important facts as 

 could be included within moderate limits. In every instance, he has 

 endeavoured to make his statements clear and precise without being 

 formal or dogmatical; and definite enough to admit of practical applica- 



