Dietary Dejicie7icies on the Suprarenal Glands. 21 



glands was 69-6 per cent. The adrenals of a polyneuritic pigeon similarly 

 treated gave wet and dry weights of 41-0 mgrm. and lO'O mgrm., and the 

 percentage of water in them was 75*6 per cent. 



Apart from increase in water-content, the fact that enlargement of the 

 cortex predominated over that of the medulla in the adrenals of pigeons fed 

 on polished rice suggests a further possible reason for the increase in weight 

 of the glands. McCarrison's observations on the occurrence of adrenal 

 enlargement in pigeons suffering from inanition have already been referred 

 to. In his feeding experiment on polished rice, the increase in weight of the 

 adrenals is associated with loss of body weight, and in my own experiments 

 loss of body weight and adrenal enlargement have been almost constantly 

 associated. 



Ellis and Gardiner (1912) have shown that in rabbits, which live normally 

 on a diet poor in cholesterol, inanition causes a rise in the content of 

 cholesterol in the blood, and Anitschow and Chalatow (1913) produced 

 adrenal enlargement in these animals by feeding with excess of cholesterol. 

 It was conceivable, therefore, that the enlargement of the suprarenals, which 

 occurs in the production of experimental polyneuritis, was the result of 

 inanition and was due to the storage in the adrenal cortex of lipoids which had 

 been set free by the breaking down of the body tissues. The validity of this 

 hypothesis was tested by observations on the cholesterol-content of the 

 adrenals of normal and polyneuritic pigeons. For this purpose the colori- 

 metric method of Grigaut (1911) was used and some concurrent estimations 

 of the cholesterol-content of the blood of such pigeons were also made by the 

 same method. Such colometric determinations were found to be most 

 accurate when the standard contained approximately the same amount of 

 cholesterol as the Ksolution to be tested. The observations in Table VIII show 

 the degree of accuracy of colorimetric estimations when this precaution was 

 taken. 



The cholesterol extracted from the adrenals was com'pared with a standard 

 containing 1'2 mgrm. of the pure substance, while for blood a standard 

 containing 3 mgrm. was used. The chief difficulty in making the estimations 

 was caused by the presence in the blood and gland extracts of organic matter 

 which altered the tint, making it greener than the standard. Screens of 

 amber glass were found to be of use in making the colour comparison in such 

 cases. 



The average results obtained in normal and polyneuritic pigeons are given 

 in Table IX. 



In pigeons fed on polished rice with extreme symptoms of polyneuritis 

 there is an increase in the percentage of cholesterol in the blood, but no 



