AUTHOR S ABSTRACT OF THIS PAPER ISSUED BY 

 THE BIBLIOGRAPHIC SERVICE, OCTOBER 27 



COMPARATIVE STUDIES ON THE GROWTH OF THE 

 CEREBRAL CORTEX 



I. ON THE CHANGES IN THE SIZE AND SHAPE OF THE CEREBRUM 

 DURING THE POSTNATAL GROWTH OF THE BRAIN. ALBINO RAT 



NAOKI SUGITA 



From The Wistar Institute of Anatomy and Biology 



TWO FIGURES AND TWO CHARTS 



I. INTRODUCTION 



The present study is preliminary to an investigation on the 

 postnatal growth of the cerebral cortex in thickness, in the case 

 of the albino rat. For this purpose it was necessary to learn the 

 changes in shape and size of brain — represented by the cerebrum 

 — which occur during postnatal growth and to record these 

 changes in terms of linear measurements. 



The growth of the brain, as represented by increase in weight, 

 is tabulated in "The Rat" (Donaldson, '15). As yet however we 

 have no records concerning the shape and dimensions of the 

 brain — or cerebrum — in relation to increasing weight or age. 

 Hatai ('07) has given detailed measurements on the skull of 

 mature albino rats, from which we can infer approximately the 

 shape and size of the adult albino rat brain, but measurements 

 for the younger stages were not included. 



As a first step in this study, I had to ascertain the relation 

 existing between the weight of the entire brain and of the cere- 

 brum during growth. For the purpose of a more detailed study, 

 Donaldson has divided the entire brain into four parts, i.e., the 

 cerebrum, the stem, the cerebellum and the olfactory bulbs, and 

 investigated the increase in weight of each of these parts and the 

 changes in the weight relations among them, during postnatal 

 growth (unpublished observations, partly presented in a Harvey 

 Lecture, December, 1916) . From a like investigation on my part, 



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