PEEFACE TO THE ELEVENTH EDITION 



ONCE more this book has been thoroughly revised. The sections 

 dealing with salivary secretion, the formation of urine, and much 

 of the chapter on respiration have been almost entirely rewritten. 

 New matter on the process of conduction in the heart, on the appli- 

 cations of physical chemistry to physiology, on so-called vitamines, 

 and several other subjects has been introduced. The concluding 

 chapter on reproduction and development is a new one, and 

 replaces the two last chapters in previous editions. 



I am again indebted to several kind friends for assistance in 

 carrying out my task. I would especially thank Mr Barcroft, F.E.S., 

 for his valuable help in the chapters that deal with saliva, respira- 

 tion, and the kidney ; Dr C. S. Myers, who has kindly revised the 

 parts which deal with the special senses ; Dr Hertz of Guy's Hospital, 

 for useful hints in bringing the chapter on the movements of the 

 stomach and intestines up to date ; and Dr F. H. A. Marshall, for 

 similar kind offices in relation to the subject of reproduction. 



I think, in conclusion, I may congratulate my readers that, 

 although the present edition contains so much that is new both 

 in text and illustrations, I have been successful in introducing this 

 additional information without increasing the bulk of the volume. 

 As a matter of fact, this edition is one page shorter than the 

 last. 



W. D. HALLIBUETOK 



KING'S COLLEGE, LONDON, 

 1913. 



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