PREFACE. XV 



many topics of great scientific interest are entirely passed over ; and it 

 is hoped that such omissions will not be accounted as faults in the esti- 

 mation of those, who dread lest the attention of the Student should be 

 too much drawn off by the seducing novelties of Science, from his less 

 attractive, but more important objetts. 



For a large part of his illustrations the Author is indebted to the 

 valuable and beautiful Icones Physiologies of Prof. Wagner. The 

 sources of all are indicated. 



In conclusion, the Author would repeat what he has already had 

 occasion to state ; that in a work involving many details, it is not to 

 be expected that no error should have crept in ; but that he has endea- 

 voured to secure correctness, by relying only upon such authorities as 

 appeared to him competent, and by comparing their statements with 

 such general principles as he considers well established. For the truth 

 of those principles he holds himself responsible ; for the correctness of 

 the details, he must appeal to those from whom they are derived, and 

 to whom he has generally referred. He hopes that he will not be found 

 unwilling to modify either, when they have been proved to be errone- 

 ous; nor indisposed to profit by criticism, when administered in' a 

 friendly spirit. 



Bristol, Feb. 1, 1842. 



