vi PREFACE. 



An addition which is likely to be welcomed, and to make the 

 book more useful, is a special chapter for students (Chapter 

 XXXVII. ). 



I had especially desired to have a chapter dealing with Tissue 

 Culture," and had asked my friend Mr. H.'M. Carleton, of Oxford, 

 to undertake it ; but as illness prevented his carrying out the work, I 

 was myself obliged at the eleventh hour to write the article. Dr. 

 A. Drew was most helpful here, and Dr. Strangeways, of Cambridge, 

 lent me some literature on the subject. 



For advice and encouragement in this arduous task I have to 

 thank my many friends. Dr. Bolles Lee sent me his blessing and 

 three hundred references ; Professor J. P. Hill placed his note- 

 books and experience at my disposal ; Dr. J. A. Murray, of the 

 Cancer Research Fund, proved a perfect mine of suggestions, and I 

 dug freely at this source. I am very grateful to both Dr. Murray 

 and his amiable staff, of w r hom Dr. Drew and Dr. Cramer have 

 helped me most. Professor Starling, of University College, Pro- 

 fessor E. S. Goodrich, of Oxford, Professor Sherrington, of Oxford, 

 Professor Boycott, of University College Medical School, Professor 

 E. B. Wilson, of Columbia University, and Professor D. M. S. 

 Watson, of University College, London, helped me in one way or 

 another. Professor W. M. Bayliss and Dr. Oscar Brady gave me 

 valuable information on certain chemical aspects. My friends at 

 the Rothamsted Station, especially Mr. Ward Cutler and Dr. Imms, 

 were very helpful. Dr. Allen, of Plymouth, and Dr. Orton kindly 

 answered inquiries. 



Great care has been taken in the preparation of the Index, and I 

 have to thank my sister for much assistance. 



In writing a book of this kind, it is difficult at times to ascertain 

 exactly who did originate some one method, and if we have occa- 

 sionally overlooked the original source we will be glad to have such 

 lapsus calami rectified in some future edition. 



Finally, it must be remarked that the arrangement and method 

 of exposition of the new material closely follows that of Dr. Bolles 

 Lee ? while the bulk of the book is still largely due to him. 



J. BRONTE GATENBY. 



UNIVERSITY COLLEGE. 

 LONDON. 



