AUTHOR'S PREFACE 



This volume endeavors to treat certain aspects of 

 biology according to the spirit and methods of the exact 

 sciences. The treatment is confined to certain funda- 

 mental problems which have been studied quantitatively. 

 These studies lead to a theory of some aspects of injury, 

 recovery, and death, as well as of antagonism and per- 

 meability. The behavior of the organism in these 

 respects may be predicted with a satisfactory degree of 

 accuracy by means of the equations which express the 

 theory in mathematical form. 



The author is under great obligation to the Marine 

 Biological Laboratory at Woods Hole for the facilities 

 generously placed at his disposal. He desires to make 

 grateful acknowledgement to Mr. F. S. Mathews and Mr. 

 Gr. B. Eay for the preparation of drawings and to Mr. 

 Lee Morrison for technical assistance in conducting 



the experiments. 



The Attthob. 



Cambridge, Mass. 



