PEEFACE. 



THE first volume of this work which appeared in the year 

 1880 formecl a complete and independent treatise on the 

 physiological chemistry of the elementary tissues of the 

 animal body, including under this designation the blood, 

 the lymph, and the chyle. 



The present volume, like its predecessor, constitutes 

 an ind ependent and complete treatise ; it deals with the 

 physiological chemistry of the digestive processes, which 

 have- been treated on the same lines as were followed in 

 Vol. I. My aims and endeavours are clearly set forth in 

 the following sentences which appeared in the preface to 

 that volume : 



' It has been a constant object with me to give the 

 reader a very full and, so far as possible, independent 

 account of the state of knowledge on the subjects discussed, 

 and I trust I may with complete truthfulness say that this 

 work is based upon a study of original memoirs, rather 

 than upon a study of text-books. In the interest of the 

 student, nearly all papers are quoted by their full titles 

 and few have been quoted which have not been thoroughly 

 read and studied. Whenever quotations have been made 

 at second hand the fact has been stated.' 



G. /, 



\ 



