PREFACE. Vll 



table individual; and, although it does not pro- 

 fess to enter fully into the explanation of the laws 

 which regulate the functions of these organic 

 structures, yet, much of physiology has been in- 

 troduced, both to illustrate the descriptions, and 

 to relieve the dry ness of the anatomical details. 

 The necessity of an accurate knowledge of struc- 

 ture, will be fully perceived in the perusal of the 

 physiological discussions which are intended to 

 form the subject of the second volume. I trust 

 that the plan of illustrating the descriptions 

 by the introduction of cuts into the body of the 

 letter-press, will be found of considerable assist- 

 ance to the student; and that the engraved plates, 

 although not all of equal merit in point of execu- 

 tion, will, nevertheless, be found sufficient for 

 conveying correct ideas of those parts, which, 

 from their minuteness, are necessarily microscopic 

 objects. 



As an apology for errors which may be detected 

 in the volume, I might plead the interruptions, 

 anxieties, and unremitting duties of very exten- 

 sive professional occupations ; but, as I am aware 

 that no author is dragged before the tribunal of 



