562 



Miscellaneous, 



titious matter is in no way connected with the idea of organisation, 

 life or nutrition. We can only learn by experience, whether or not 

 the introduction of new matter is attended by the secretion of 

 such matter as has become useless. It is not inconceivable that a 

 parasitical plant, for instance, may receive nothing except assimilable 

 nourishment ; it is therefore very conceivable that nutrition can exist 

 in plants without a secretion of excrements, more especially if the 

 secretion of gases and aqueous vapours is not considered of that 

 nature. But in treating every problem, not merely chemical, Dr. 

 Liebig cannot penetrate beyond the surface. What follows contains 

 nothing but analogies, with which physiology knows not what to do. 

 Such are the solution of albumen in an infusion (not decoction, as Dr. 

 Liebig says) of the acid of the stomach of a calf, the transformation 

 of starch into sugar by means of a decoction of malt (not barley, as 

 Dr. Liebig says). But who is it that puts a decoction of malt to the 

 germinating grain of rice ? Dr. Liebig should have known that, if indeed 

 there be in nature operations resembling those of life, they neverthe- 

 less differ ; and that the physiologists do not look for what is possi- 

 ble and conceivable, but for what really exists. Here, as on other 

 occasions Dr. Liebig mentions with contempt the " vital force" of 

 physiologists ; but he evidently does not know the meaning of the 

 term, or he would speak of it differently. By this expression is im- 

 plied the fundamental cause of all (all, without exception) the 

 processes of life. Dr. Liebig is always talking, as if vital force was 

 applied only to a few operations related to chemical facts, which, ne- 

 vertheless, are just those which are most unimportant. The forma- 

 tion of form is the result of vital power, and a most important one ; 

 it is obvious that this has no connexion with chemistry. Even where 

 our author treats of mere chemical relations, there is still something 

 in his reasoning which shows that he tries to conceal his superficial 

 propositions behind phrases. He asserts that plants secrete what is 

 not assimilable ; but why just what is not assimilable } Why not 

 what is assimilated ? In what way does the plant distinguish one 

 from the other ? Why does it not secrete fluids through its leaves, 

 and aeriform fluids through its roots ? Why, because of their peculiar 

 nature ; and it is just this peculiar nature which is called by us vital 

 power, until we shall acquire more just ideas, and be able to express 



