MODERN BIOLOGY 379 



mostly distinguishes living from dead matter. But, all the same, it is not to 

 be supposed that living creatures and their organs are, as Bichat imagined, 

 independent for their functions of the laws of inorganic nature; on the con- 

 trary, heat and cold, electricity and chemical reagents exercise a law-bound 

 influence on them just as they do on dead matter. But vital phenomena defi- 

 nitely differ from the processes of inorganic change on account of their con- 

 stant alternation of regeneration and dissolution, of building up and breaking 

 down. This relation between the vital phenomena and the general physio- 

 chemical conditions that govern them Bernard calls "determinism," a term 

 that he would substitute for "vitalism" and "materialism," both of which 

 he rejects. For in contrast to Magendie he considers hypotheses and theories 

 useful to science; they possess, it is true, little real value, but they are never- 

 theless inevitable, "for in every science it is impossible to proceed from a 

 known fact to an unknown fact without the aid of an abstract idea or the- 

 ory." And yet the general view of life is the business of the research-worker 

 himself; "no one asks whether Harvey or Haller were spiritualists or mate- 

 rialists; we only know that they were great physiologists, and it is their 

 observations and experiments that have been handed down to posterity." 

 Bernard thus sought to compromise between the sheer unimaginative estab- 

 lishing of facts, and speculation that in its efforts to create a general theory 

 of existence loses sight of those fundamental realities which form the vital 

 conditions of all natural science. 



His investigations into nutrition 

 Bernard's fame, however, does not by any means rest primarily on the theo- 

 retical view of life that he propounded. It is as a practical pioneer in the 

 sphere of experimental biology that he has acquired so great a name. His 

 investigations have especially aimed at following up the process of nutri- 

 tion and metabolism in the animal body, and the result he attained created 

 in many respects an entirely new conception of them. In particular, he 

 showed clearly for the first time the function of the liver in the process of 

 digestion; he established the percentage of sugar in the liver and studied the 

 conditions under which this secretion takes place. Likewise, entirely new 

 light was thrown by him on the part played by the liver in the body's 

 economy in general; the liver is characterized by him as " un veritable labora- 

 toire vital." Whereas after the discovery of the lymphatic system the liver 

 was considered to be merely an organ for the preparation of bile, Bernard 

 found that a number of substances from the intestine are conveyed through 

 the cystic vein and are transformed there. Thus, thanks to him, the knowl- 

 edge of the absorption of nourishment in the digestive canal was placed on 

 a new basis. In connexion with this subject Bernard studied the production 

 of sugar in the human body and in animal bodies in general. He established 

 the fact that a stab in the medulla oblongata of an animal causes diabetes — a 



