TRANSLATOR'S PREFACE vii 



features in the plan of chemical function in the animal 

 economy. To the publishers he would here express his ap- 

 preciation of their unfailing kindness and consideration in 

 spite of many annoying delays in the preparation of the 

 material for publication, arising from the pressure of de- 

 mands in other lines which at the time seemed insistent. 



A. J. S. 



