378 THE MUSCLE-TISSUE. 



laevorotatory, while the common form and its salts are optically 

 inactive. 



INOSIT. 



Of the origin of inosit, which is apparently a constant constituent 

 of muscle-tissue, but which is found also in other organs of the 

 body, and appears in the urine when polyuria is either artificially 

 produced or results from some morbid process, nothing is known. 

 It is not peculiar to the animal world, however, but occurs widely 

 distributed in the vegetable kingdom also, and is identical with the 

 so-called phaseo-mannite, which is especially abundant in certain 

 beans. In muscle-tissue it is found only in traces. 



The substance is not a carbohydrate, as was once supposed, but 

 belongs to the aromatic series, and is commonly regarded as hexa- 

 hydroxybenzol : 



CH.OH 



OH.HC/ X CH.OH 



OH.HC.xCH.OH 

 CH.OH 



In pure form it crystallizes in colorless, monoclinic prisms, which 

 are often grouped in rosettes. It melts at 217 C. It is soluble 

 in water and dilute alcohol, but is insoluble in absolute alcohol and 

 ether. The substance does not reduce the metallic oxides in alka- 

 line solution, and is optically inactive. It is not fermentable with 

 common yeast, but is decomposed by the Bacterium lactis with the 

 formation of lactic acid, and subsequently yields butyric acid. 



Tests. Scherer's Test. If a few crystals of inosit are evaporated 

 on platinum foil with a little nitric acid, and the residue is treated 

 with ammonia and a drop of dilute solution of calcium chloride, a 

 rose-red spot remains on further evaporation. The reaction is due 

 to the formation of rhodizonic acid. 



Gallois' Test. On evaporating a small amount of a solution of 

 inosit and adding a few drops of a dilute solution of mercuric 

 nitrate before the residue has become dry, a yellow spot develops 

 on the further application of heat, which ultimately turns red. On 

 cooling, the red color disappears, but reappears on heating. 



Isolation. To demonstrate the presence of inosit in muscle- 

 tissue, this is finely hashed, and extracted with hot water, when the 

 albumins are removed by boiling. The filtrate is precipitated with 

 barium hydrate, so as to remove the phosphates that are present. 

 After filtering the liquid is then concentrated, until most of the 

 kreatin has separated out. This is removed by filtration ; the fil- 

 trate is boiled with four times its volume of alcohol ; the solution 

 is allowed to cool, freed from the mineral constituents that have 

 separated out, and shaken with ether. The inosit then separates 

 out in the form of fine platelets, which can be further purified by 

 dissolution in alcohol and reprecipitation with ether. 



