PEEFAOE TO SECOND EDITION. 



food. To satisfy and stimulate just such appetites is, I am 

 sure, very desirable. 



I recommend notliing in this treatise that I have not 

 proved valuable by actual trial, unless I mention some emi- 

 nent person as advising it ; nor do I announce any fact or 

 scientific truth that I have not verified, except as I give it on 

 the authority of some competent person. 



For most of the figures of the second edition lam indebted 

 to one of my pupils, Mr. W. L. Holdsworth, whose skill as 

 an artist needs no praise. 



Appended to this volume is a very full index which mil be a 

 great aid to the student 



