KIDNEYS. 329 



It contained besides a substance insoluble in boiling water. 

 The aqueous solution of the dried mass had no taste, and neither 

 reacted as an acid nor as an alkali. Even after adding to it an 

 acid, it was not precipitated by prussiate of potash ; but it was 

 thrown down by acetate of lead, corrosive sublimate, and by the 

 infusion of nut-galls. The portion insoluble in ammonia had 

 not altered its appearance. Dilute caustic potash dissolved it 

 with difficulty, or even not at all while cold. But, by the appli- 

 cation of a moderate heat, it was slowly but completely dissolved. 

 Acetic acid, being added in excess, precipitated the portion in- 

 soluble in that reagent. 



From these reactions it follows that the solid portion of the 

 kidney is neither fibrin nor cellular tissue. It approaches near- 

 est to the fibrous coat of the arteries, and probably, therefore, is 

 little else than a congeries of blood-vessels. 



The liquid of the kidney separated from the fibrous matter, 

 the characters of which have been just described, was muddy and 

 mucilaginous, and resembled milk. When heated to nearly the 

 boiling point it coagulated into a mass so thick that it was neces- 

 sary to boil it with an additional quantity of water, in order to 

 be able to separate the coagulum from the liquid portion. This 

 coagulum was dried and digested in ether, which separated a 

 considerable quantity of fatty matter. The residue when mois- 

 tened with water assumed its original appearance. It was dis- 

 solved in caustic potash, and acetic acid added in great excess. 

 The matter described above as insoluble in acetic acid was pre- 

 cipitated. From this it was evident that the coagulum was al- 

 bumen mixed with capillary blood-vessels. 



The liquid separated from the coagulum was acid. When 

 evaporated it left a yellow extract mixed with saline crystals. 

 Alcohol of 0-8333 dissolved from it a yellowish acid extractive 

 matter, together with some common salt. And the matter re- 

 maining after the action of the alcohol was precisely the same 

 as the corresponding substance obtained from the liquid expressed 

 from muscle. It was mostly soluble in water, and the solution 

 when evaporated left a pale yellow, transparent, hard substance, 

 which contained phosphates. It was copiously precipitated by 

 lime-water. What the water had left undissolved was soft, white, 

 and semitransparent. It was soluble in hot water, from which it 

 was precipitated by tannin. 



