22 



ANIMAL CHEMISTRY 



the above named organs ; because the or- 

 gans cannot create it from the other elements 

 presented to them; and, finally, because no 

 nitrogen is absorbed from the atmosphere in 

 the vital process. 



The substance of the brain and nerves 

 contains a large quantity of albumen, and, 

 in addition to this, two peculiar fatty acids, 

 distinguished from other fats by containing 

 phosphorus (phosphoric acid?) One of 

 these contains nitrogen (Fremy.) 



Finally, water and common fat are those 

 ingredients of the body which are destitute 

 of nitrogen. Both are amorphus or unor- 

 ganized, and only so far take part in the 

 vital process as that their presence is re- 

 quired for the due performance of the vital 

 functions. The inorganic constituents of 

 the body are, iron, lime, magnesia, common 

 salt, and the alkalies. 



IX. The nutritive process m the carni- 

 vora is seen in its simplest form. This class 

 of animals lives on the blood and flesh of 

 the graminivora ; but this blood and flesh 

 is, in all its properties, identical with their 

 own. Neither chemical nor physiological 

 differences can be discovered. 



The nutriment of carnivorous animals is 

 derived originally from blood ; in their sto- 

 mach it becomes dissolved, and capable of 

 reaching all other parts of the body ; in its 

 passage it is again converted into blood, 

 and from this blood are reproduced all 

 those parts of their organization which have 

 undergone change or metamorphosis. 



With the exception of hoofs, hair, fea- 

 .hers, and the earth of bones, every part of 

 the food of carnivorous animals is capable 

 of assimilation. 



In a chemical sense, therefore, it may be 

 said that a carnivorous animal, in support- 

 ing the vital process, consumes itself. That 

 which serves for its nutrition is identical 

 with those parts of its organization which 

 are to be renewed. 



The process of nutrition in graminivorous 

 animals appear at first sight altogether dif- 

 ferent. Their digestive organs are less sim- 

 ple, and their food consists of vegetables, 

 the great mass of which contains but little 

 nitrogen. 



From what substances, it may be asked, 

 is the blood formed, by means of which their 

 organs are developed ? This question may 

 be answered with certainty. 



Chemical researches have shown, that all 

 such parts of vegetables as can afford nutri- 

 ment to animals contain certain constituents 

 which are rich in nitrogen ; and the most 

 ordinary experience proves that animals re- 

 quire for their support and nutrition less of 

 these parts of plants in proportion as they 

 abound in the nitrogenized constituents. 

 Animals cannot be fed on matters destitute 

 of these nitrogenized constituents. 



These important products of vegetation 

 are especially abundant in the seeds ol the 

 different kinds of grain, and of pease, beans, 

 and lentils: i the roots and the iuices of 



what are commonly mailed vegetables. They 

 exist, howevej, in all plants, without excep- 

 tion, and in every part of plants in larger or 

 smaller quantity. 



These nitrogenizea forms of nutriment in 

 the vegetable kingdom may be reduced tc 

 three substances, which are easily distin* 

 guished by their external characters. Two 

 of them are soluble in water, the third is 

 insoluble. 



When the newly expressed juices of 

 vegetables are allowed to stand, a separation 

 takes place in a few minutes. A gelatinous 

 precipitate, commonly of a green tinge, is 

 deposited, and this, when acted on by liquids 

 which remove the colouring matter, leaves 

 a grayish white subtance, well known to 

 druggists as the deposit from vegetable juices. 

 This is one of the nitrogenized compounds 

 which serves for the nutrition of animals, 

 and has been named vegetable Jibrine. The 

 juice of grapes is especially rich in this 

 constituent, but it is most abundant in the 

 seeds of wheat, and of the cerealia. It may 

 be obtained from wheat flour by a mechani- 

 cal operation, and in a state of tolerable 

 purity ; it is then called gluten, but the glutin- 

 ous property belongs, not to vegetable fibrine, 

 but to a foreign substance, present in small 

 quantity, which is not found in the other 

 cerealia. 



The method by which it is obtained suffi- 

 ciently proves that it is insoluble in water j 

 although we cannot doubt that it was origi- 

 nally dissolved in the vegetable juice, from 

 which it afterwards separated, exactly as 

 fibrine does from blood. 



The second nitrogenized compound re- 

 mains dissolved in the juice after the sepa- 

 ration of the fibrine. It does not separate 

 from the juice at the ordinary temperature, 

 but is instantly coagulated when the liquid 

 containing it is heated to the boiling point. 



When the clarified juice of nutritious 

 vegetables, such as cauliflower, asparagus, 

 mangel wurzel, or turnips, is made to boil, 

 a coagulum is formed, which it is absolutely 

 impossible to distinguish from the substance 

 which separates as coagulum, when the 

 serum of blood or the white of an e:g, 

 diluted with water, are heated to the boiling 

 point. This is vegetable albumen. It is 

 found in the greatest abundance in certain 

 seeds, in nuts, almonds, and others, in 

 which the starch of the grammese is re- 

 placed by oil. 



The third nitrogenized constituent of the 

 vegetable food of animals is vegetable caserne. 

 It is chiefly found in the seeds of pease, 

 beans, lentils,, and similar leguminous seeds. 

 Like vegetable albumen, it is soluble in 

 water, but differs from it in this, that its 

 solution is not coagulated by heat. When 

 the solution is heated or evaporated, a skin 

 forms on its surface, and the addition of an 

 acid causes a coagulum, just as in animal 

 milk. 



These three nitrogenized compounds, ve- 

 getable fihrine. albumen, and r.aseine, are 



