SUPRARENAL GLAND—EFFECTS OF INANITION 200 
the adult; in the middle zone (outer part) from 33 per cent to 
10 per cent; in the middle zone (inner part) from 28 per cent to 
16 per cent; in the inner cortical zone from 28 per cent to 21 
per cent; in the medulla from 46 per cent to 10 per cent. 
7. In the underfed young rats stunted three to ten weeks or 
more, the suprarenal cells may increase in size (outer part of 
middle zone), or decrease (inner cortical zone and inner part of 
middle zone), or remain nearly unchanged. The nuclei are 
similarly variable, with slight changes in the relative volume. 
In the stunted rats refed one or two weeks, the cells and nuclei 
in general approach, but have not yet reached, their normal size. 
8. In adult acute inanition there is but little change in the size 
of the cells and nuclei in the outer and inner cortical zones. In 
the middle zone and medulla, however, there is a marked loss in 
size of the cells, though but slight loss in the nuclei (with corre- 
sponding increase in relative nuclear volume). In chronic adult 
inanition there is a greater decrease in the size of the outer- and 
middle-zone cells, but about the same as during acute inanition 
in the inner zone and medulla. The nuclear loss is somewhat 
greater than during acute inanition, with relative nuclear volume 
not very different from normal, except in the middle zone (where 
it is high). 
9, Amitosis in the suprarenal of the rat is infrequent and of 
doubtful significance. Mitoses are frequent in the new-born (av- 
erage about 20 per section), but fewer at the end of the first week 
(10 per section). They increase to a maximum rate during the 
second and third weeks, slowly decreasing in number thereafter, 
although occasionally found even in the adult. Mlitoses are 
most frequent in the outer zone and outermost part of the middle 
zone (these forming the ‘germinative zone,) less frequent in the 
medulla, and rare in the inner cortical zone. 
10. In young rats stunted by underfeeding, mitosis is more or 
less completely suppressed in the suprarenal. On refeeding one 
week, mitosis begins again, and in two weeks the normal rate is 
reestablished. Cell division in the suprarenal is therefore con- 
trolled by the amount of nutrition. 
