GLUTIN. 393 



solutions of gelatin ; the latter in a dilute state precipitate a little 

 bone-earth. Of the organic acids, tannic add is the only one 

 which throws down a precipitate from a solution of glutin ; the 

 precipitate is white and cheesy, and is observable even if the glu 

 tin be dissolved in 5000 times its weight of water. 



The only earthy and metallic salts which precipitate glutin are 

 corrosive sublimate, bichloride of platinum, and sulphate of 

 bin oxide of platinum. Ferrocyanide of potassium does not affect 

 either its neutral or its acid solution Chlorine, bromine, and iodine, 

 on the other hand, act very powerfully on a solution of glutin ; 

 chlorine causes the separation of a coagulum which is partially 

 thready, and after prolonged action, compounds are formed of 

 chlorous acid and undecomposed glutin. Creosote gives a milky 

 appearance to the clear solution ; the salts of alumina, suboxide 

 of mercury, the oxides of silver, copper, and lead, and of protoxide 

 and peroxide of iron, exhibit no reactions when added to a solu- 

 tion of glutin, or, at most, cause only a very slight turbidity ; and 

 the same is the case with basic acetate of lead. Basic sulphate of 

 binoxide of iron when added to a solution of glutin, causes a bulky 

 precipitate, which, when dried, is of a deep red colour. 



Moist glutin exposed to the air soon undergoes putrefaction ; 

 it first becomes sour, but afterwards developes a large quantity of 

 ammonia ; according to Gannal,* the gelatigenous tissues are the 

 first of the solid animal structures to become putrid. 



Dry glutin when heated softens, swells up, evolves an odour of 

 burned horn, does not easily catch fire, and after burning for a very 

 short time, leaves a voluminous, blistered, glistening coal, which 

 after perfect combustion, yields a somewhat varying amount of 

 phosphate of lime. The products of its dry distillation are those 

 of the animal tissues generally ; it yields, however, a preponderat- 

 ing quantity of carbonate of ammonia. 



When boiled with concentrated nitric acid, glutin becomes 

 gradually converted into oxalic and saccharic acids, and into two 

 substances resembling suet and tannic acid. It dissolves in con- 

 centrated sulphuric acid, forming a colourless fluid, which on 

 boiling gradually yields leucine, glycine, and other substances. If 

 however it be treated with sulphuric acid and peroxide of manganese 

 or bichromate of potash, it yields, according to Schlieperf and 

 GuckelbergerJ, most of the non-nitrogenous acids of the firs 



* Hist, de 1'embaumement, etc. Paris, 1838 

 t Ann. d. Ch. u. Pharm. Bd. 59, S. 1-32. 

 % Ibid. Bd. 64, S. 39-100. 



