CLAUDE BERNARD 573 



portant results have been mentioned above. Other experiments and 

 writings confirmed, extended and defended his views. Bernard had 

 made a great discovery and pushed it to the end and did not have to 

 suffer the humiliation so often falling to the lot of a pioneer who pro- 

 nounces a great fundamental truth and is outstripped by his contempo- 

 raries in producing proofs and developing details. Though it took sev- 

 eral years to work out all the details, he always kept the lead. 



This discovery supplied much that had been obscure concerning the 

 sugar metabolism in the body and the functions of the liver, and 

 greatly influenced general biological thought. It overthrew the idea 

 that animals can not construct but only destroy products built up by 

 plants. It broke down the prevailing theory that each organ has only 

 one function. Previous work had shown that the liver produces bile 

 and the pancreas and stomach furnish digestive juices. Nothing more 

 seemed left to be learned except the function of the spleen. The dis- 

 covery of the second function of the liver destroyed the bonds which the 

 theory of functions had thrown around the biological thought of the 

 time and encouraged more work in this field. The introduction of the 

 idea of an internal secretion which was poured into the blood to assist 

 in the normal nutrition of the body has been very productive and still 

 fills the minds of physiologists and bids fair to produce some of the most 

 valuable contributions to modern physiology. 



Glycogen was soon found in all the tissues and quantitative relations 

 were investigated. Others have contributed but little new to the subject 

 and Bernard's ideas stand to-day as he expressed them then. 



He, in the matter of glycogen, not only laid the very first stone, but left a 

 house so nearly finished that other men have been able to add but little. 



During this work, Bernard discovered the remarkable fact that a 

 puncture of the fourth ventricle of the brain causes temporary diabetes. 

 This, like other of his discoveries, was not happened upon accidentally, 

 but was the result of logical reasoning concerning the nervous control 

 of the sugar production by the liver, which he assumed to be a typical 

 internal secretion. He found that cutting the vagus nerve stopped the 

 sugar production and reasoned that stimulation of the nerve should 

 lead to increased production. Being unsuccessful when all the ordi- 

 nary means of nerve stimulation were used, he resorted to an expedient 

 which he had noted previously, that a marked stimulation occurred when 

 the point of origin of the nerve in the brain was punctured. In this 

 case, an over-production and excretion of sugar was obtained. Here, 

 as in a number of instances, a wrong view led him to an important dis- 

 covery for he soon showed that the vagus is not a true secretory nerve 

 governing the hepatic sugar secretion. 



This illustrates one of Bernard's important characteristics. He de- 



