







PEEFACE TO THE TWELFTH EDITION. 



IT has been found necessary to make a considerable number of 

 alterations in the Twelfth Edition of Kirkes' Physiology. Many of 

 these have been in the earlier chapters, and in the sections on The 

 Blood, The Heart, and The Muscular System ; while the chapters on 

 The Nervous System, on The Reproductive Organs, and on Develop- 

 ment have been re-arranged and to a great extent re-written. About 

 fifty new illustrations have been added. In those chapters which treat 

 of the subjects of which the junior student is expected to exhibit a 

 knowledge at his first examination, some details which may be omitted 

 on first reading have been printed in smaller type; they must not, 

 however, be considered for this reason to be unimportant. 



Without attempting to enumerate all the important text-books on 

 Physiology and monographs on physiological subjects of which use has 

 been made in preparing the present edition, and to the authors of 

 which we beg to record our obligations, we would mention especially 

 those of Drs. Gaskell, Gowers, Halliburton, and Wooldridge ; Landois 

 and Stirling's Text-book, and the works of the late Prof. F. M. Bal- 

 four. Dr. Gowers has kindly allowed us to copy several of the 

 diagrams from his works on the Nervous System. 



Our thanks are due to Dr. T. W. Shore, who has kindly helped us 

 in revising and seeing through the press certain sections, particularly 

 those relating to biological questions. 



Mr. Daniellson has undertaken, as in the two previous editions, the 

 drawings upon wood and the engraving of all the new illustrations, and 

 has carried out the work with much skill. 



W. MORRANT BAKER. 

 VINCENT D. HARRIS. 



