380 ALBUMEN, CASEUM. 



when moist, is a highly elastic and flexible substance ; dried, it loses 

 about 30 per cent, of water, and becomes brittle, horny, semi-trans- 

 parent. Thrown into water, it gradually imbibes all it had lost by 

 drying, and regains its former properties. Burned and incinerated, 

 fibrine leaves a quantity of ash, which consists, for the major part, 

 of phosphate of lime, with which is mixed a small quantity of phos- 

 phate of magnesia and of oxide of iron. 



Albumen exists in large quantity dissolved in the water or serum 

 of the blood, and in the white of tbe egg ; it is also found in almost 

 all the animal fluids that are not excretions, or destined to be thrown 

 off as useless to the system. Albumen, as familiarly known, has 

 the remarkable property of coagulating or setting into a soft fluid, at 

 a certain temperature — 158° Y. 



Caseum, or caseine, is the distinguishing principle of milk. By 

 combining with acids it forms an insoluble compound ; and it under- 

 goes a remarkable coagulation, as all the world knows, in contact 

 with a piece of the inner membrane of the stomach of a young ani- 

 mal : from a fluid it sets into a soft solid, which by degrees separates 

 into two portions — whey and curd. The curd, or caseum, always 

 contains fat, and, when burned, leaves a considerable quantity of 

 ash. 



Physiologists distinguisl> three principal tissues in the bodies of 

 animals ; the muscular, the nervous, and the cellular. 



The muscular tissue consists of an assemblage of contractile fibres, 

 here disseminated through the masses of organs, there colh.'cted into 

 bundles and constituting the tlesh. This is the instrument by which 

 animals perform all tlicir voluntary motions, and it is that also by 

 "which all the active but involuntary movements of the body are ex- 

 cited. Muscular flesh is always a compound substance, however ; it 

 consists of fibrine, the contractile or proper elenjent, albuujen, fat, 

 gelatine, an odorous extractive matter, lactic acid, dilTercnt salts and 

 the coloring principle of the blood. 



Put into cold water, so h)ng as the temperature is below from 130° 

 to 110" F., little etfect is produced beyond the solution of the soluble 

 salts which it may contain, and of a }>ortion of its extractive matter 

 and albumen. At from 175" to 195", the albumen which had been 

 dissolved, coagulates and rises to the top as scum, and the fat melts 

 and floats on the surface. The fil)rinous element of the meat, how- 

 ever, preserves its characters even after the action of boiling water 

 continued for some time. 



The nervous tissue constitutes the brain, spinal marrow, and 

 nerves, distributed to all parts of the body. Brain in its composition 

 contains a large quantity of water, — 80 percent. — certain fatly mat- 

 ters, albumen, osmazono, phosphorus in combination with fat, sul- 

 phur, and phosphates of potash, lime, and iiKii^nesia. The c»)mposition 

 of the brain of animals, the dog, the sheep, the ox, appears to be 

 very analogous to that of the human subject. 



Cellular tissue is the general connecting medium throughout the 

 animal body, and is not only met with, it may be said, everywhere, 

 but forms a main element in many of the textures of the body, such 



