AUTHOR’S ABSTRACT OF THIS PAPER ISSUED 
BY THE BIBLIOGRAPHIC SERVICE, MARCH 17 
THE RELATIVE VOLUMES OF THE CORTEX AND 
MEDULLA OF THE ADRENAL GLAND IN 
THE ALBINO RAT 
JOHN C. DONALDSON 
Department of Anatomy, School of Medicine, University of Cincinnati 
FOUR CHARTS 
This study was undertaken at the suggestion of Dr. H. H. 
Donaldson to determine the relations of the cortical and medul- 
lary portions of the adrenal gland in the albino rat, M. nor- 
vegicus albinus, and to demonstrate the changes in their volume 
which take place with age. 
In the albino rat at birth there is a fairly well-marked cortex 
and medulla in the adrenals, though there are numerous groups 
of medullary cells still scattered through the cortex. Within a 
few days most of these have disappeared and the cortex and 
medulla are sharply marked off from one another. There are 
present in the albino rat, in addition to the tissues in the adrenal, 
microscopic masses of chromaffin cells in the retroperitoneal 
tissue, Fulk and Macleod (16), and a small but constant mass 
of cortical cells in the epididymis of the testis, Swale Vincent 
(12). No attempt was made to include these extra-adrenal 
masses in this study. 
The materials used were the adrenal glands from seventeen 
rats, nine males and eight females, of Wistar Institute stock. 
The glands were fixed in Bouin’s solution. After having been 
stored in cedar oil, they were passed through xylol, embedded 
in paraffin, and cut into serial sections 10 » thick. The sections 
were stained with haematoxylin and eosin. This gives a very 
sharp contrast between the cortex and the medulla, the latter 
showing as a blue mass in the surrounding pink-stained cortex. 
Every tenth section was projected with an enlargement of fifty 
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