282 INTERNAL SECRETION 



found that, in the suprarenal cortex of a human embryo 5 cm. 

 long, all the cells contained granules, though these were smaller 

 in size and in number than in the adult. In an embryo 12 to 15 

 cm. long, the granules had increased considerably in size, and 

 were much more numerous, especially in the peripheral cells. 

 These conditions are maintained through the later developmental 

 stages, and change very little during the post-embryonal period. 

 The comparative maximal number of cortical granules is reached 

 during the second six months after birth ; from then onwards the 

 number is subject to variation which is largely unexplained. But 

 an increase in the number of granules in the cortex is by no 

 means to be regarded as the result of fatty degeneration. Plecnik's 

 experiments shed important light upon the nature of the cortical 

 granules, because he applied to the suprarenals the test which 

 Lewinson gives for fats, namely, a modification of Weigert's 

 chrome-ha?matoxylin stain for the medullary sheath of the nerves. 

 He found that, after the suprarenals had been hardened for some 

 time in Miiller's mixture, the granules in the cortex were stained 

 blue in exactly the same manner as the fat in the interstitial cells 

 of the testicles, while subepicardial fat and the fat of phosphorus 

 kidney did not stain by this method. The granules in suprarenals 

 treated by this method frequently colour black after treatment 

 with Altmann's mixture and rinsing in water. This is not the 

 case, however, with subepicardial fat and phosphorus kidney fat. 

 By means of i per cent, osmic acid, Bernard and Bigart (1902) 

 were able to differentiate between two cell types, or more properly, 

 two cell conditions, in the external layer of the zona fasciculata, the 

 so-called zona spongiosa. Of these two cell types, one contained 

 larger or smaller globules of common fat which stained in the 

 usual manner with osmium, \vhile the other contained granules 

 which, in response to osmium, took on a shade varying from light 

 to dark grey. Mulon next showed that the grey granules are 

 soluble in turpentine, xylol, bergamot oil, and cedar-wood oil. 

 The cells known as spongiocytes are, according to Mulon, cells 

 the protoplasm of which is filled with granules resembling fat. 

 Their spongy appearance is merely the result of the secondary 

 solution of the globules during mounting. Bernard and Bigart 

 call this substance " labile fat," and consider that it is a product 

 of normal cell-function, while ordinary fat may, under conditions, 

 be a pathological product. Bernard, Bigart and Labbe believe 

 that labile fat is lecithin or a mixture of lecithins. By extraction 

 with ether and alcohol, they estimated both the total amount of 

 fat and the total amount of phosphorus in the suprarenal, and 

 found that the proportion of the phosphorus fat to the whole 

 amount of fat was as follows : 45-3 : 100 in the horse, 48.8 : 100 in 

 the sheep, 52.7 :ioo in the rabbit. In the horse, the phosphorus 

 fat forms 6.77 per cent, of the organ ; in man the proportion of 

 lecithin fat to the whole amount of fat is 13.1 : 100, the lecithin fat 



