THE CHEMICAL COMPOSITION OF THE BODY. 125 



Galactose is formed from lactose by the action of dilute mineral 

 acids, or inverting ferments ; it may also be obtained from cerebrin. It 

 undergoes alcoholic fermentation, and reduces copper salts to the sub- 

 oxide. 



Inosite. Inosite occurs in the heart and voluntary muscles, as well 

 as in beans and other plants. It crystallizes in the form of large color- 

 less nionoclinic tables, which are soluble in water, but insoluble in alco- 

 hol or ether. It has the formula of glucose, but is not a sugar. Inosite 

 may be detected by evaporating the solution containing it nearly to dry- 

 ness, and by then adding a small drop of solution of mercuric nitrate, and 

 afterward evaporating carefully to dryness, a yellowish-white residue is 

 obtained ; on further cautiously heating, the yellow changes to a deep 

 rose-color, which disappears on cooling, but reappears on heating. If 

 the inosite be almost pure, its solution may be evaporated nearly to dry- 

 ness. After the addition of nitric acid, the residue mixed with a little 

 ammonia and calcium chloride, and again evaporated, yields a rose-red 

 coloration. 



Certain of the monatomic Fatty Acids are found in the body, 

 viz., Formic CH 2 O 2 , acetic C 2 H 4 2 , and propionic C 3 H 6 3 , present in 

 sweat, but normally in no other human secretion. They have been found 

 elsewhere in diseased conditions. Butyric acid, C 4 H 8 2 , is found in 

 sweat. Various others of these acids have been obtained from blood, 

 muscular juice, faeces and urine. 



Of the diatomic fatty acids, one acid, Lactic acid, C 2 H 6 3 , exists in a 

 free state in muscle plasma, and is increased in quantity by muscular 

 contraction, is never contained in healthy blood, and when present in 

 abnormal amount seems to produce rheumatism. 



Of the aromatic series, Benzoic acid, C 3 H 6 2 , is always found in 

 the urine of herbivora, and can be obtained from stale human urine. It 

 does not exist free elsewhere. 



Phenol. Phenyl alcohol or carbolic acid exists in minute quantity in 

 human urine. It is an alcohol of the aromatic series. 



Inorganic Principles. 



The inorganic proximate principles of the human body are numerous. 

 They are derived, for the most part, directly from food and drink, and 

 pass through the system unaltered. Some are, however, decomposed on 

 their way, as chloride of sodium, of which only four-fifths of the quantity 

 ingested are excreted in the same form ; and some are newly formed 

 within the body, as, for example, a part of the sulphates and carbo- 

 nates, and some of the water. 



Much of the inorganic saline matter found in the body is a necessary 

 constituent of its structure, as necessary in its way as albumin or any 



