INOSIT. 359 



phoric acid. This liberates the lactic acid from its salts, while the 

 chlorides and sulphates remain unaU'ected. The lactic acid is then 

 extracted with ether. The ether is distilled oil', the residue boiled 

 with water and an 6X0668 of carbonate of zinc, and filtered while still 

 hot. The filtrate is concentrated to a small volume, when on stand- 

 ing, and especially alter the addition of a small amount of alcohol, 

 the /iiic lactatc crystalli/es out. To separate the paralactate from 

 the common lactatc, which, as I have said, is also found in trace- in 

 the muscle-tissue, the crystals are placed in absolute alcohol, which 

 dissolves the paralactate (solubility 1 : 1100), while the common form 

 is insoluble. They are then finally dried and weighed. 



To obtain the lactic acid as such the lactates are decomposed with 

 hydrogen sulphide. The resulting zinc sulphide is filtered off, 

 washed with water, when filtrate and washings are evaporated at 

 70 C. to a small volume. 



Both acids are amorphous, and are obtained in the form of a thick 

 syrup, which is soluble in water, alcohol, and ether. Of their salts, 

 the /inc salts are especially characteristic and serve to distinguish 

 the two forms from each other. As I have indicated, the common 

 lactatc is insoluble in absolute alcohol. It crystallizes with three 

 molecules of water, which escape at a temperature of 105 C., so 

 that the loss of weight will then correspond to 18.18 per cent. The 

 paralactate, on the other hand, is soluble in absolute alcohol, though 

 with difficulty, and crystallizes out with only two molecules of water, 

 which likewise escapes at 105 C. In this case the loss of weight 

 amounts to 12 per cent. Both the free acid and the paralactate are 

 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/^CH.OH 



I I 

 OH.HC\ /CH.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 



