LIEBIG'S THEORY OF ALIMENTS. 911 



its connexion with the turning of thousands of 

 wheels at a distance from the piston rod, appear 

 incomprehensible." 



Liebig further maintains, that the proximate 

 constituents of the blood and organized tissues of 

 animals are all originally produced in the or- 

 ganism of plants, that " all such parts of vege- 

 tables as can afford nutriment to animals, contain 

 constituents rich in nitrogen," that "animals 

 require for their support and nutrition less of 

 these parts of plants in proportion as they abound 

 with nitrogenized constituents," that " no nitro- 

 gen is absorbed from the atmosphere in the vital 

 process," yet that " the chief ingredients of the 

 blood in all animals, contain nearly 17 per cent, 

 and no part of an organ less than 17 per cent, of 

 nitrogen," that " in the absence of starch, sugar, 

 fat, gum, &c., the oxygen of the atmosphere com- 

 bines with the tissues," that "the metamor- 

 phosis in existing tissues, and consequently their 

 restoration or reproduction, must go on far less 

 rapidly in graminivora than in carnivora," that 

 starch, sugar, gum, fat, pectin, bassorine, wine, 

 beer, spirits, and all substances not containing 

 nitrogen, are incapable of being transformed into 

 blood, and serve merely to support respiration ; 

 but that as flesh, vegetable fibrin, albumen, and 

 caseine, contain the proximate constituents of 

 blood and the animal tissues ready formed, they 

 alone are capable of supporting the nutrition 



