No. 12. 



Of the Substances of Animals. 



3G9 



bone, it rarely exceeds from 35 to 40 per 

 cent, of the whole weight. 



The incombustible portion consists for the 

 most part of phosphate and carbonate of 

 lime. The relative proportions of these 

 two earthy compounds also vary with the 

 kind of animal, with its age, its condition, 

 its food, and its state of health. To form 

 100 lbs. of bone, the animal will usually re- 

 quire to incorporate with its own substance 

 about 



35 pounds of gelatine. 



55 pounds of phosphate of lime, 

 4 pounds of carbonate of lime, 

 3 pounds of phosphate of magnesia, 

 3 pounds of soda, potash, and common salt. 



100 



Hair, horn, and wool, are distinguished 

 from the muscular parts of the aniinal body 

 by the large proportion — about five percent. 

 — of sulphur which they contain. They 

 consist of a substance which in other re- 

 spects closely resembles gluten and gelatine 

 in its chemical composition. When burned, 

 they leave from one to two per cent, of ash, 

 which in the case of a variety of human 

 hair, which left 1.1 per cent, of ash, was 

 found by Van Laer to consist of 



Per cent. 



Soluble chlorides and sulphates 0.51 



Oxide of iron 0.39 



Phosphate and sulphate of lime, ) q^q 

 Phosphate of magnesia and silica j ~^ 



The inorganic matter contained in hair, 

 is therefore, generally speaking, the same 

 in kind as that which exists in the muscular 

 fibre and in the bone. It contains the same 

 phosphates of lime and magnesia — the same 

 sulphates and the same chlorides, among 

 which latter common salt is the most abun- 

 dant. The absolute quantity ot ash or inor- 

 ganic matter varies, as well as the relative 

 proportions in which the several substances 

 are mixed together in the different solid 

 parts of the body, but the substances them- 

 selves of which the inorganic matter is com- 

 posed are nearly the same, whether they be 

 obtained from the bones, from the muscles, 

 or from the hair. 



Of the fluid parts of the body, the blood 

 is the most important, and by far the most 

 abundant. The body of a full grown man, 

 of moderate dimensions, contains about 12 

 lbs. of blood,* that of a full grown ox, six 

 times as heavy, cannot contain less than 70 

 or 80 lbs. Blood consists of about 



* Lehmann, Physiologische Chemie, I., pp. 113 and 

 338. 



Per cent. 



Water 80 



Organic matter 19 



Saline matter 1 



100 



The organic matter consists chiefly of 

 fibrin, which, when the blood coagulates, 

 forms the greater part of the clot — and of 

 albumen, which remains dissolved in the 

 serum or fluid part of clotted blood, but 

 which, like the white of egg, runs together 

 into insoluble clots when the serum is heated. 



The saline matter remains dissolved in the 

 serum after the albumen has been separated 

 by heating, and consists chiefly of phosphates, 

 sulphates, and chlorides — nearly the same 

 compounds as exist in the soluble part of the 

 ash left by the solid parts of the body. 



Besides this soluble saline matter which 

 remains in the serum, a portion of phosphate 

 of lime and a small quantity of phosphate of 

 magnesia exist also in the fibrin and in the 

 albumen of the blood. Thus in the dry 

 state these substances contam respectively 

 of the mixed phosphates 



Albumen of ox blood 1.8 per cent. ) /t,.,„ i:„„-. 



Fibrin of human blood . . 0.7 per cent. ] (,oerzeiius.; 



Thns the same saline and earthy com- 

 pounds, which form so large a portion of 

 the bones, are distributed every ichere in 

 sensible proportions throughout all the more 

 important solids and fluids of the body. 



Whence does the body derive all the sub- 

 stances of which its several parts consist? 



The answer to this question appears at 

 first sight to be easy. They must be ob- 

 tained from the food. But when the inquiry 

 is further considered, a reply to it is not so 

 readily given. 



It is true, indeed, that the organic part of 

 the food contains carbon, hydrogen, o.xygen, 

 and nitrogen — the elements of which the 

 organic parts of the body are composed. 

 The m-organic matter also which exists in 

 the food contains the lime, the magnesia, the 

 potash, tiie soda, the sulphur, the phospho- 

 rus, and the iron, which exist in the inor- 

 ganic parts of the animal body — .so that the 

 question seems already resolved. The body 

 obtains from the food all the elements of 

 which it consists, and if these be not present 

 in the food, tlie body of the animal cannot 

 be properly built up and supported. 



But to the chemist and physiologist, the 

 more important part of the question still re- 

 mains. In what state do these elements 

 enter into the body? Are the substances of 

 which the food consists decomposed after 

 they are taken into the stomach"! Are their 

 parts first torn asunder, and then reunited 

 in a difl^erent way, so as to form the chemi- 



