The source 
of animal 
heat is 
oxidation, 
18 ON THE: PLACE OK faiSaaN 
clear intellect of Liebig, grasping the meaning of 
various isolated experiments of workers in all countries 
and devising methods for observation not known 
before, elaborated the ‘Thier Chemie,’ which he gave 
to the world in 1840. England received it simulta- 
neously with Germany in- the translation ‘Animal 
Chemistry, the preparation of which was entrusted 
to Dr. Gregory, one of his pupils. 
Though others had been previously feeling their 
way here and there, and had made slight inroads on 
the borders of a then unknown realm of research, he 
was the first to push boldly on, exploring with instru- 
ments of his own invention, and to point to further 
conquests waiting to be made in the domain of the 
Chemistry of Organised Beings. 
That with all his energy he was but a partial 
explorer he knew full well, but that he had mapped 
out the right lines in laying down “oxidation” as the 
source of animal heat he felt confident, Oxidation, it 
seems, always gives rise to heat (p. 6 and Appendix.) 
It is strange—or, remembering Lumanum est errare, 
perhaps it was not strange—that he should fall into 
the very error he so strongly deprecates in others— 
that of drawing conclusions from an insufficient number 
of observations. While, as repeated subsequent expe- 
riments have shown, he was right in pointing to the 
oxidation of carbon as a source of animal heat, he 
missed the track in the explanation of the source of 
muscular power. His theory, that muscular work was 
accompanied by the destruction of muscular substance 
itself, could not be verified. On the contrary, whether 
little or much muscular work is done seems to have 
hardly any effect. As the destruction of muscular 
