PREFACE. IX. 



Secondly, it is hoped that the student, having acquired the technique 

 necessary to determine the course of the metabolic changes in the 

 normal individual, will be encouraged to extend his observations 

 to those occurring in disease. Progress in medical science is largely 

 dependent on the statistical method. I am convinced that a con- 

 siderable body of trained medical men making accurate analyses 

 of the abundant clinical material that must inevitably come their 

 way will advance our knowledge much more rapidly than a few 

 isolated specialists, who are apt to confine their attention to subjects 

 in advanced disease. It is the border-land between health and ill- 

 health that particularly requires exhaustive investigation, and 

 for its exploration a whole army is required. We can safely rely 

 on the Medical Research Committee for the Staff work necessary 

 for the proper co-ordination of the results. 



I am much indebted to my friends and colleagues, Mr. H. 

 Raistrick and the Hon. H. Onslow, for valuable help in the chapter 

 on the preparation of the amino-acids, and for many suggestions 

 made after reading the proofs of the early chapters. Miss E. C. 

 Travell has given me great assistance in the preparation of the 

 index. 



To ensure a supply of the necessary apparatus and materials, 

 arrangements have been made by Messrs. Baird and Tatlock 

 (London), by which they hope shortly to be able to maintain a stock 

 of all the apparatus and chemicals mentioned. I am indebted to 

 them for kindly supptying a considerable number of new illus- 

 trations of the apparatus used in the Laboratory. 



Finally, I wish to record my sincere gratitude to Prof. Hopkins 

 for the many valuable criticisms and suggestions that have helped 

 me to develop what he is pleased to consider a satisfactory course 

 for the students attending his lectures. 



SYDNEY W. COLE. 



BIOCHEMICAL LABORATORY, 



CAMBRIDGE, 

 May, 1919. 



