240 THE DUCTLESS GLANDS 



occur in the cells and become filled with fluid. This first 

 occurs in the centre of the cells. Then the pigment appears 

 in the form of granules at the border of the vacuolated part 

 of the cells. 



Labbe concluded that what Bernard and Bigart called 

 " labile fat " is lecithin or a mixture of lecithins. He 

 made an estimation, on the one hand, of the total fat by 

 extraction with ether and alcohol, and, on the other hand 

 the total quantity of phosphorus contained in the adrenal 

 bodies, and found that the ratio of phosphorized fat to the 

 total fat is 45-3 : 100 in the horse, 48-8 : 100 in the sheep, 

 5? -7 : 100 in the rabbit. The phosphorized fat constitutes 

 6*77 per cent, of the organs in the horse ; in man the ratio of 

 the lecithin to the total fat is 13-1 : 100 ; the lecithin amounts 

 to 2-08 per cent, of the total weight. The lipoids are in- 

 creased after muscular labour. 



Babes believes that the pigment of the zona reticularis 

 arises from the lipochrome of the fatty layer. When the 

 organ is very rich in fat, this is deposited in crystalline, 

 doubly refracting structures resembling protagon in their 

 reactions. 



It is by no means clear that these lipoid (phosphorized fat) 

 granules represent the actual secretion of the adrenal cortex. 

 Nor, if such were the case, is it possible at the present time 

 to suggest any reasonable theory as to their function. 1 (See, 

 however, pp. 235-248.) 



1 Ciaccio claims that the lipoids in any tissue may be distinguished from 

 the neutral fats by the following histological method : (1) Fixation for 

 twenty-four to forty-eight hours in the following fluid : 



Five per cent. pot. bichrom. .. .. .. 100 c.c. 



Formalin . . . . . . . . 20 c.c. 



Acetic acid . . . . . . . . . . 5 c.c. 



(2) Five to eight days in potassium bichromate solution, 3 per cent. (3) Run- 

 ning water, twenty-four hours. (4) Alcohol, twenty-four hours. (5) Absolute 

 alcohol, two hours. (6) Xylol. (7) Paraffin. 



The sections are stained with a saturated solution of Sudan III. in 80 per 

 cent, alcohol. 



According to Ciaccio, the droplets in the tissues shown by this method 

 consist of lecithin and other lipoids. 



Bell has shown, however, that potassium chromate acts upon droplets 

 of neutral fat in the tissues as well as upon the lipoids. It is certain that some 

 lipoids, such as cholesterin, fatty acid mixtures, cerebroside, etc., are much 

 more readily chromated than neutral fat. But the size of the droplet of 

 neutral fat is a factor of great importance. A small droplet of triolein is com- 



