APR.] CHEMICAL BASIS OF THE ANIMAL BODY. 731 



direct alcoholic fermentation to detect any intermediate change of the lactose into 

 any other fermentable sugar. 



Lactose is however directly capable of undergoing the lactic and 

 butyric fermentations ; the circumstances and products are the same as 

 in the case of dextrose (see above). The action is generally productive 

 of a collateral small quantity of alcohol. 



Lactose is thus distinguished from dextrose by its smaller solubility 

 in water, insolubility in alcohol, crystalline form, lower cupric oxide re- 

 ducing power and its incapability of undergoing direct alcoholic fermen- 

 tation. 



Preparation. After the removal of the casein and other proteids of 

 the milk, the mother liquor is evaporated to the crystallising point ; the 

 crystals are purified by repeated crystallisation from warm water. 



4. Inosit. C 6 H 12 O G + 2H 2 O. 



This substance occurs but sparingly in the human body; it was 

 found originally by Scherer 1 in the muscles of the heart. Cloetta shewed 

 its presence in the lungs, kidneys, spleen and liver 2 , and Miiller in the 

 brain 3 . It occurs also in diabetic urine, and in that of 'Bright's disease,' 

 and is found in abundance in the vegetable kingdom. 



Pure inosit forms large efflorescent crystals (rhombic tables); in 

 microscopic preparations it is usually obtained in tufted lumps of fine 

 crystals. Easily soluble in water, it is insoluble in alcohol and sether. 

 It possesses no action on polarised light, and does not reduce solutions 

 of metallic salts. 



It admits of no direct alcoholic, but is capable of undergoing the 

 lactic fermentation; according to Hilger 4 the acid formed is sarcolactic. 

 It is unaltered by heating with dilute mineral acids. 



Preparation. It may be precipitated from its solutions by the action 

 of basw lead acetate and ammonia ;. the lead is then removed by sulphu- 

 retted hydrogen and the inosit precipitated with excess of alcohol. 



As a special test (Scherer's} may be mentioned the production of a 

 bright violet colour by careful evaporation to dryness on platinum foil, 

 with a little ammonia and calcium chloride. 



5. Dextrin. C U H 10 O 5 . 



By boiling starch-paste with dilute acids, or by the action of fer- 

 ments, the starch is converted into an isomeric body, to which, from its 

 action on polarised light, the name dextrin has been given. It is soluble 



1 Ann. d. Chem. u. Pharm. Bd. 73, S. 322. 2 Ibid. Bd. 99, S. 289. 



8 Ibid. Bd. 103, S. 140. Ibid. Bd. 160, S. 333. 



