OF HAIR, HORN, AND WOOL, AND OF BLOOD. 589 



ing, the same in kind as that which exists in the muscular fibre and in 

 the bone. It contains the same phosphate of lime and magnesia — the 

 same sulphates and the same chlorides, among which latter common salt 

 is the most abundant. The absolute quantity of ash or inorganic matter 

 varies, as well as the relative proportions in which the several substances 

 are mixed together in the ditferent solid parts of die body, but the sub- 

 stances themselves of which the inorganic matter is composed are nearly 

 the same, whether they be obtained from the bones, from the muscles, or 

 from the hair. 



2°. Of the jiaid parts of the body, the blood is the most important, 

 and by far the most abuifdant. The body of a full grown man, of mo- 

 derate dimensions, contains about 12 lbs. of blood, [Lehniaim, Physi- 

 ologische Chemie, I., pp. 113 and 338,] that of a full grown ox, six 

 times as heavy, cannot contain less than 70 or 80 lbs. Blood consists of 

 about — 



Per cent. 



Water 80 



Organic matter 19 



Saline matter 1 



100 

 The organic matter consists chiefly o^ Jibrin, which, when the blood 

 coagulates, forms the greater part of the clot — and of^ albumen, which re- 

 mains 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, sul- 

 phates, and chlorides — nearly the same compounds as exist in the soluble 

 part of the ash left Ijy the solid parts of the body. 



Besides this soluble saline matter which remains in tlie serum, a por- 

 tion 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 contain respectively of the mixed phosphates- 

 Albumen of ox blood . . . . 1*8 per cent. } /jy i- \ 

 Fibrin of human blood .... 0-7 per cent. ^ V^erzeims.) 



Thus the same saline and earthy compounds, which form so large a 

 portion of the bones, are distributed every where in sensible proportions 

 throughout all the more important solids and fluids of the body 



§ 2. Whence does the body obtain these substances 1 Are they contained 

 in the food ? 



Whence does the body derive all the substances of which its several 

 parts consist ? 



The answer to this question appears at first sight to be easy. They 

 must be obtained from the food. But when the enquiry is further con- 

 sidered, a reply to it is not so readily given. 



It is true, indeed, that the organic part of the food contains carbon, 

 hydrogen, oxygen, and nitrogen — the elements of which the organic parts 

 of tlie body are composed. The in-organic "flatter also which exists in 

 25* 



