THE SUPRARENAL CAPSULES. 465 



The nature of the poisonous agent is still uncertain, but 

 the interesting facts have been further made out that it is 

 confined to the medulla of the glands, that it is absent from 

 the suprarenals in cases of Addison's disease, and that the 

 physiological effects are produced by doses compared to 

 which those of homoeopaths are gigantic. Schafer esti- 

 mates that one-millionth of a gramme per kilogramme of 

 body weight is sufficient to produce physiological effects. 

 The effect is transitory, the poison apparently being packed 

 away and rendered innocuous in certain organs which can- 

 not at present be satisfactorily specified. 



It should be added that the extracts of the glands used 

 were prepared with water, with alcohol of various strengths, 

 and with glycerine. They are made either from the fresh 

 or dried gland, or by boiling for a few minutes. The prin- 

 ciple is not soluble in absolute alcohol or ether. The ani- 

 mals experimented on were chiefly dogs, but cats, rabbits, 

 guinea-pigs, and a monkey gave confirmatory results. 



As a general conclusion, Professor Schafer inclines to 

 the theory of internal secretion as against that of auto- 

 intoxication; the gland forms something which is distributed 

 to the muscles, and is essential for their normal tone ; when 

 the gland is removed the toxic effects seen are the result of 

 the absence of this internal secretion. 



Although, as just stated, the chemical nature of this 

 remarkable substance is still uncertain, there have been 

 some researches directed to determining what it is. B. 

 Moore 1 considers that it is identical with a powerful re- 

 ducing substance found only in the medulla of the gland, 

 and first described by Vulpian. 2 At any rate the solubilities 

 of this reducing material are identical with those of the 

 active physiological principle. It gives a dark green or 

 blue colour with ferric chloride passing through purple to a 

 dark red on the addition of ammonia or sodium carbonate. 

 With chlorine, bromine, or iodine water, peroxide of hydro- 

 gen or alkalis in the presence of oxygen, it gives a rose-red 



1 "Proceedings of Physiological Society," p. xiv., 1895 (contained in 

 vol. xvii., Journal of Physiology). 



2 Compt. Rend., xliii. and xlv. 



