ERRORS OF LIEBIG. 901 



oxygen with carbon and hydrogen in the lungs, 

 is sufficiently demonstrated by the facts, that the 

 temperature of the blood is elevated while passing 

 through the lungs, and diminished while passing 

 through the systemic capillaries, where it ought 

 to be raised, if oxygen there combined with car- 

 bon and hydrogen. Yet Liebig asserts, that 

 " arterial and venous blood have the same tem- 

 perature.'' (p. 272.) It is therefore evident, that 

 his whole theory of respiration and animal heat 

 is fundamentally erroneous ; while in some re- 

 spects it is even more defective than that of 

 Black, Lavoisier, Crawford, and Dalton, who 

 maintained rightly, that animal heat is evolved 

 in the lungs, and given up by the blood to the 

 solids in the systemic capillaries ; but without 

 explaining what office it 'performs in any of the 

 vital functions. And so far is it from being true, 

 as maintained by Liebig, that " the globules of 

 the blood take no share in the nutritive process," 

 that they are far more abundant in arterial than 

 in venous blood, as proved by the numerous 

 experiments of Prevost and Dumas, Denis, Le 

 Canu, Mayer r Autenreith, Berthold, Letellier, and 

 others. It is therefore manifest, that while pass- 

 ing through the systemic capillaries, a portion of 

 them are dissolved, expended in nourishing the 

 solids, and in maintaining the various secretions. 

 It is one of the most extraordinary facts in the 

 history of modern science, that Liebig should 



