PEEFACE. 



rFIHE following Appendix has been written upon the same lines 



as in former editions, save that it has been enlarged, and in 

 reality now constitutes a treatise on the chemical substances 

 occurring in the animal body. As in former editions it is entirely 

 the work of Dr A. Sheridan Lea. 



The references given though extensive are not intended to be 

 exhaustive. An effort has been made to make the references to 

 recent work as complete as possible ; other references are to papers 

 which themselves give full references and will therefore serve as a 

 guide to the literature of the subject; and some have been in- 

 serted in order to inform the student of the dates at which 

 important results were first described. 



We desire to express our thinks to Messrs Winter of Heidel- 

 berg for the six figures which have been taken from Krukenberg's 

 Grundriss der medicinisch-chemischen Analyse, and to Prof. Kuhne 

 for the large number which have been taken from his Lehrbuch der 

 physiologischen Chemie (1868). A few have been drawn in wood 

 from the plates in Funke's Atlas der physiologischen Chemie 

 (1858). 



We are also indebted to Dr S. Ruhemann for reading the 

 proofs from page 91 to page 216, in which the text contains 

 many formulae, and involves special chemical knowledge. 



The volume is paged separately from the rest of the Text Book, 

 and has an index of its own. Indeed it may be regarded as an 

 independent work. The references to the body of the Text Book 

 are given in paragraphs. 



M. FOSTER. 



A. SHERIDAN LEA 



July, 1892. 



