vi Preface 



As these "Growth Problems" occupied my husband's studies 

 and interests perhaps to a greater extent than did any other 

 of the varied Biological work undertaken by him, this small 

 memorial volume may be of special interest to those who knew 

 him as researcher and teacher. It is now published in the hope 

 that it may fulfil his constant wish to inspire others to delve 

 into this, to him, fascinating field of research. It represents the 

 summation of work and thought carried on for more than twenty 

 years. 



FRANCES A. E. ASSHETON. 



GRANTCHESTBR, 



April, 1916. 



