276 Cc. M. JACKSON 
11. The three cortical zones of the suprarenal are distinguish- 
able from birth and well differentiated at three weeks. Lipo- 
somes (lipoidal granules or droplets) are present in considerable 
amount at birth, being rather uniformly distributed through 
the cortex and the cortical strands through the medulla. They 
increase slowly rather and the distribution changes. They be- 
come more abundant in the outer zone and outer half of the 
middle zone, decreasing in amount toward the inner zone, with 
none in the medulla. The inner cortical zone is atrophic in char- 
acter, with cells in various stages of degeneration and absorption. 
Pigment (lipochrome) appears in these cells after eight weeks of 
age. The degeneration and absorption of this zone is associated 
with the expansion of the medulla in the morphogenesis of the 
suprarenal gland. The absorption of the inner cortical zone dur- 
ing the growth of the suprarenal is characteristic for mammals, 
though greatly exaggerated in the human infant. The chromaf- 
fin reaction of the medulla is weak at birth, becoming well marked 
in the rat after the age of three weeks. 
12. In the young rats stunted by underfeeding certain cell 
changes occur in the suprarenal. The cortex tends to undergo 
the normal differentiation of liposomes, but their amount is 
variable. In some cases many of the cells appear atrophic and 
degenerative, especially toward the inner cortical zone, where 
the process is extreme. Pigment appears in unusual abundance. 
The medulla is usually less affected, although pyenotic nuclei 
frequently occur. Only in extreme cases is there any appreciable 
decrease in the chromaffin reaction. In stunted rats refed two 
weeks the structure is already gaining a normal appearance, 
though some areas of degeneration persist. 
13. In adult rats subjected to acute or chronic inanition the 
suprarenal cells present a simple atrophy, together with a vari- 
able amount of degeneration. The nuclei may be either hypo- 
chromatic or hyperchromatic, with frequent pyenosis or karyoly- 
sis. The liopsomes are retained tenaciously in the outer zone, 
though usually decreased to a considerable extent in the rest of 
the cortex, especially in extreme inanition. The pigment re- 
mains unchanged. The medulla cells show degenerative changes, 
