1865—1870 136 



disease known as diabetes and which is characterized, as every- 

 body knows, by a superabundance of sugar in the whole of 

 the organism, the urine often being laden with it. But how is 

 it, wondered Claude Bernard, that the quantity of sugar ex- 

 pelled by a diabetic patient can so far surpass that with which 

 he is provided by the starchy or sugary substances which form 

 part of his food ? How is it that the presence of sugary matter 

 in the blood and its expulsion through urine are never com- 

 pletely arrested, even when all sugary or starchy alimentation 

 is suppressed? Are there in the human organism sugar-pro- 

 ducing phenomena unknown to chemists and physiologists? 

 All the notions of science were contrary to that mode of think- 

 ing; it was affirmed that the vegetable kingdom only could 

 produce sugar, and it seemed an insane hypothesis to suppose 

 that the animal organism could fabricate any. Claude Bernard 

 dwelt upon it however, his principle in experimentation being 

 this: **When you meet with a fact opposed to a prevailing 

 theory, you should adhere to the fact and abandon the theory, 

 even when the latter is supported by great authorities and 

 generally adopted.'^ 



This is what he imagined, summed up in a few words by 

 Pasteur — ■ 



*'Meat is an aliment which cannot develop sugar by the 

 digestive process known to us. Now M. Bernard having fed 

 some carnivorous animals during a certain time exclusively 

 with meat, he assured himself, with his precise knowledge of 

 the most perfect means of investigation offered him by 

 chemistry, that the blood which enters the liver by the portal 

 vein and pours into it the nutritive substances prepared and 

 rendered soluble by digestion is absolutely devoid of sugar; 

 whilst the blood which issues from the liver by the hepatic 

 veins is always abundantly provided with it. . , . M. Claude 

 Bernard has also thrown full light on the close connection 

 which exists between the secretion of sugar in the liver and the 

 influence of the nervous system. He has demonstrated, with 

 a rare sagacity, that by acting on some determined portion of 

 that system it was possible to suppress or exaggerate at will 

 the production of sugar. He has done more still; he has dis- 

 covered within the liver the existence of an absolutely new 

 substance which is the natural source whence this organ draws 

 the sugar that it produces/' 



Pasteur, starting from this discovery of Claude Bernard's, 



