NOTES AND LITERATURE 



BIOMETRICS 



Some Recent Studies on Growth — The problems presented by 

 the phenomena of growth change are not only peculiarly adapted 

 to quantitative treatment, but perhaps more obviously and 

 clearly demand the application of quantitative methods for their 

 solution than does any other single large class of biological 

 problems. In the study of variation and heredity it is an open 

 question as to what relative importance is to be assigned to quan- 

 titative as compared with qualitative differences between organ- 

 isms. But however much interest or significance qualitative 

 changes occurring in connection with the growth process may 

 have, it yet remains an indisputable fact thai the fundamental 

 and essential feature of the process is a quantitative change. 

 While this has, of course, always been recognized by students of 

 the subject, there still is to be seen evidence of the influence of 

 the modern biometric standpoint in recent studies in this field. 

 This is chiefly apparent in the increasing attention paid to pre- 

 cision and refinement in the mathematical methods used in the 

 analysis of the distinctively quantitative phases of the problems 

 of growth. 



Professor H. H. Donaldson 1 and his students dealing with vari- 

 ous phases of the problem of growth in the white rat is in some 

 respects to be regarded as the most fundamental which has yet 

 appeared. This paper gives in detail the basic data regarding 

 the growth of the body as a whole and of the central nervous 

 "system in the white rat which have been collected in the course 

 of a very extensive and thorough investigation. These data are 

 given in a "general table" occupying thirteen pages and com- 

 prise records for 458 male and 215 female normal white rats. 

 For each of these animals (with the few omissions of single 

 measurements in scattered individuals unavoidable in so large 

 a piece of work) there are recorded the following data: Series 



1 Donaldson, H. H. A Comparison of the Albino Eat with Man in 

 Eespect to the Growth of the Brain and of the Spinal Cord. Jown. of 

 Comp. Neurol, and Psychol., Vol. XVIII, pp. 345-392, Plates II and HI, 

 1908. 



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