DIGESTION COMPARED TO FERMENTATION. 



37 



in the analysis of the precipitate above de- 

 scribed, prepared by potash, which is free 

 from inorganic matter. (22.) 



Viewed in this light, the chief constituents 

 of the blood and the caseine of milk may be 

 regarded as compounds of phosphates and 

 other salts, and of sulphur and phosphorus, 

 with a compound of carbon, nitrogen, hy- 

 drogen, and oxygen, in which the relative 

 proportion of these elements is invariable; 

 and this compound may be considered as the 

 commencement and starting point of all 

 other animal tissues, because these are all 

 produced from the blood. 



These considerations induced Mulder to 

 give to this product of the decomposition of 

 albumen, &c., by potash, the name of pro- 

 teine (from jrgomy*, " I take the first rank.") 

 The blood, or the constituents of the blood, 

 are consequently compounds of this proteine 

 with variable proportions of inorganic sub- 

 stances. 



Mulder further ascertained, that the in- 

 soluble nitrogenized constituent of wheat 

 flour (vegetable fibrine,) when treated with 

 potash, yields the very same product, pro- 

 teine; and it has recently been proved that 

 vegetable albumen and caseine are acted on 

 by potash precisely as animal albumen and 

 caseine are. 



4. As far, therefore, as our researches 

 have gone, it may be laid down as a law, 

 founded on experience, that vegetables pro- 

 duce, in their organism, compounds of pro- 

 teine ; and that put of these compounds of 

 proteine the various tissues and parts of the 

 animal body are developed by the vital force, 

 with the aid of the oxygen of the atmosphere 

 and of the elements of water.* 



Now, although it cannot be demonstrated 

 that proteine exists ready formed in these 

 vegetable and animal products, and although 

 the difference in their properties seems to in- 

 dicate that their elements are not arranged 

 in the same manner, yet the hypothesis of 

 the pre-existence of proteine, as a point of 

 departure in developing and comparing their 

 properties, is exceedingly convenient* At 

 all events it is certain that the elements of 

 these compounds assume the same arrange- 

 ments when acted on by potash at a higli 

 temperature. 



All the organic nitrogenized constituents 

 of the body, how different soever they may 

 be iu composition, are derived from proteine. 

 They are formed from it, by the addition or 

 subtraction of the elements of water or of 

 oxygen, and by resolution into two or more 

 compounds. 



* The experiment of Tiedemann and Gmelin, 

 who found it impossible to sustain the life of geese 

 by means of boiled white of egg, may be easily 

 explained, when we reflect that a graminivorous 

 animal, especially when deprived of free motion, 

 cannot obtain, from the transformation or waste 

 of the tissues alone, enough of carbon for the re- 

 spiratory process. 2 Ibs. of albumen contain only 

 3^ oz. of carbon, of which, among the last pro- 

 ittcts of transformation, a fourth part is given off 

 in he form of uric acid. 



5. This proposition must be received as 

 an undeniable truth, when we reflect on the 

 developement of the young animal in the 

 egg of a fowl. The egg can be shown to 

 contain no other nitrogenized compound ex- 

 cept albumen. The albumen of the yolk is 

 identical with that of the white ; (23) the 

 yolk contains, besides, only a yellow fat, in 

 which cholesterine and iron may be detected. 

 Yet we see in the process of incubation, 

 during which no food and no foreign matter, 

 except the oxygen of the air, is introduced, 

 or can take part in the developement of the 

 animal, that out of the albumen, feathers, 

 claws, globules of the blood, fibrine, mem- 

 brane and cellular tissue, arteries and veins, 

 are produced. The fat of the yolk may 

 have contributed, to a certain extent, to the 

 formation of the nerves and brain ; but the 

 carbon of this fat cannot have been em- 

 ployed to produce the organized tissues in 

 which vitality resides, because the albumen 

 of the white and of the yolk already con- 

 tains, for the quantify of nitrogen present, 

 exactly the proportion of carbon required 

 for the formation of these tissues. 



6. The true starting-point for all the 

 tissues is, consequently, albumen; all ni- 

 trogenized articles of food, whether de- 

 rived from the animal or from the vegeta- 

 ble kingdom, are converted into albumen 

 before they can take part in the process of 

 nutrition. 



All the food consumed by an animal be- 

 comes in the stomach soluble, and capable 

 of entering into the circulation. In the pro- 

 cess by which this solution is effected, only 

 one fluid, besides the oxygen of the air, 

 takes a part ; it is that which is secreted by 

 the lining membrane of the stomach. 



The most decisive experiments of physio- 

 logists have shown that the process of 

 chymification is independent of the vital 

 force ; that it takes place in virtue of a purely 

 chemical action, exactly similar to those 

 processes of decomposition or transforma- 

 tion which are known as putrefaction, fer- 

 mentation or decay (eremacausis). 



7. When expressed in the simplest form, 

 fermentation, or putrefaction, may be de- 

 scribed as a process of transformation that 

 is, a new arrangement of the elementary- 

 particles, or atoms, of a compound, yielding 

 two or more new groups or compounds, and 

 caused by contact with other substances, 

 the elementary particles of which are them- 

 selves in a state of transformation or decom- 

 position. It is a communication, or an im- 

 parting of a state of motion, which the 

 atoms of a body in a state of motion are ca- 

 pable of producing 1 in other bodies, whose 

 elementary particles are held together only 

 by a feeble attraction. 



8. Thus the clear gastric juice contains a 

 substance in a state of transformation, by 

 the contact of which with those constituents 

 of the food which, by themselves, are in- 

 soluble in water, the latter acquire, in virtue 

 of a new grouping of their atoms, the pro- 



