158 WHAT DOES MAN LIVE UPON? 



are exceedingly different in their character. One part of 

 the opposition was not directed against the views, such as 

 I have already been permitted to detail them, but against 

 the very indefensible rudeness with which Liebig depre- 

 ciated sciences which were wholly strange to him, and indis- 

 criminately defamed the men who opposed him, while at 

 the same time he displayed the grossest ignorance in these 

 studies. Another portion of the objections comes from the 

 ignorant and narrow-minded heads of the old school of 

 naturalists, who are devoid of no less than everything, but 

 particularly of a solid acquaintance with physics and 

 chemistry, which would fit them to give an opinion on 

 these points. Lastly, another portion arose out of a mis- 

 understanding which Liebig himself gave occasion to, by 

 want of clearness of comprehension, and by faulty expres- 

 sion of his views. It was imagined, namely, that this 

 theory of the interchange of matter through the three 

 kingdoms of Nature, was intended for a theory of animal 

 and vegetable life, and therefore it was thought that this 

 theory itself might be overturned, by pointing out that very 

 much remained unexplained and obscure, and that very 

 many things could not be made to square with it. But the 

 relation of that grand theory to animal and vegetable life, 

 is quite a different one. Those general outlines are in 

 themselves firmly and unshakeably completed and esta- 

 blished.* But in regard to the vegetable and animal king- 

 doms, they only afford us guiding maxims, in accordance 

 with which we are to attempt the more exact delineation 

 of the picture ; according to which we have to discrimi- 

 nate as to the admissibility of hypotheses in individual 

 cases; and it may be, that we have yet long to seek 



* See Liebig, " Chemistry and Physics in Relation to Physiology 

 and Pathology," 8vo. London, 1847. 



