efficiency of the apparatus in the elimination of poisons with the 

 natural kidney. Administering to a rabbit 1 gram of sodium salicylate, 

 an extraction as rapid as 3 per cent in one-half hour has been observed, 

 which compares very favorably with the normal action of the kidneys; 

 in the case of a dog ^vith the same dose, using another apparatus, 4 

 per cent was obtained in the first hour and a total of about 20 per cent 

 in sixteen hours. Better results may be confidently expected with an 

 apparatus having more surface in proportion to the volume. Potas- 

 sium iodide also passes through the membrane readily as does phenol- 

 sulphonphthalein. Of the substances naturally present in the body, 

 sugar, phosphates, diastase and other substances diffuse in notable 

 amount. 



Ethyl sulphide, (C^H5)^S, which is so readily evolved from dogs' 

 urine on the addition of lime-water or other alkali, may be obtained 

 in like manner from the diffusate, showing that the mother-substance 

 of this malodorous compound is freely eliminated by our apparatus. 



A wide field of investigation is opened up by the use of this apparatus 

 in a comparative study of the blood flowing to and from various or- 

 gans ^vith reference both to the substances which they extract from, 

 or add to, the general circulation and to the special active principles 

 (hormones, etc.) which may be present in their internal secretions. A 

 beginning in this direction has been made by attaching the apparattis 

 to the portal vein, (four experiments), the blood of which gave by 

 diffusion considerably more amino-acids (determined by Van Slyke's 

 method) than that of the carotid. Work in this direction, as well as 

 in the improvement of the apparatus for the various purposes above 

 outlined and accumulation of the experience necessary along these 

 lines, is being pushed actively forward. A full description of the ap- 

 paratus, with directions for its use, together with the results, will ap- 

 pear in the January number (1914) of the Journal of Pharmacology 

 and Experimental Therapeutics. 



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