FROM THE PREFACE 



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 pro- 

 ceeding further ; and he was not without hope that some Writer, more 

 fully competent to the^task, might in the mean time 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 antiquated, have not been replaced by any works that can be considered 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 compendi- 

 ous in their bulk for the limited time at the disposal of most Students, 

 and sufficiently 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 expe- 

 rienced 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 appli- 

 cation, without appearing to be unimprovable by further inquiry. Phy- 

 siology is essentially a science of progress ; and it must happen that 

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