356 RECENT ADVANCES IN SCIENCE. 



ucts of digestion were carried from the intestine, not straight to the 

 tissues which they were destined in any case ultimately to nourish, 

 but to the liver, there to undergo transformation and await some future 

 fate, marked the beginning of a new way of looking at the problems 

 of nutrition. It was recognized that these became less simple — more 

 complex than they had formerly seemed; but the very complexity 

 gave hope of possible solutions. It was seen that as the blood swept 

 in the blood stream through the several tissues it might undergo pro- 

 found changes without any visible outward token, such as that of the 

 appearance of secretion in the duct of a gland or of the contraction of 

 a muscle — might undergo changes which could only be demonstrated 

 by differences in the composition or properties of the blood as it 

 came to or left this or that tissue. The technical difficulties of the 

 analysis of blood prevented any immediate marked steps in the way 

 of advance, and attempts to establish in respect to any particular tissue 

 the changes which the blood underwent in it, by inference from the 

 results of experimental interference, met with difficulties of another 

 but no less serious kind. Hence the world had to wait some little time 

 before the new idea which Bernard's discovery had started bore impor- 

 tant or striking fruit. Yet it was not very long before it was seen that 

 the hepatic cell had heavy duties touching the metabolic changes of 

 proteid as well as a carbohydrate material; that it, and not the kidney 

 alone, had to do with urea as well as sugar, and the difficulties, which 

 physiologists in the early half of this century must have keenly felt — 

 how to reconcile the bald task of secreting bile, which alone technical 

 physiology alloted to the liver, with the overweening importance which 

 not only popular experience, but more exact clinical study, could not 

 but attach to that organ — began to steal away. A little later on exact 

 experimental inquiry converted into certainty the suspicions which 

 clinical study had raised, that the blood in streaming through the 

 thyroid gland underwent changes of supreme importance to the nutri- 

 tion of the tissues of the body at large. Still, a little later, the Ber- 

 nardian idea, if I may so venture to call it, doubling, so to speak, on 

 itself, led to the discovery that the mysteries of the fate of sugar in 

 the body were not lodged in the liver alone, but might be traced to the 

 pancreas. It was seen that as the blood streaming through the liver 

 worked on sugar besides secreting bile, so the pancreas, besides secret- 

 ing its marvellous omnipotent juice, also influenced, though in a differ- 

 ent way, the career of sugar in the body; that the disease we call 

 diabetes was or might be in some way connected with the pancreas no 

 less than with the liver. I need not go on to speak of recent researches 

 on the suprarenal capsules or of other organs. It is enough to note 

 that one of the most promising lines of inquiry at the present day is 

 that relating to the changes of which I am speaking, sometimes known 

 under the name of "internal secretion." Every year — nay, almost 

 every month — brings up some new light as to the details of the great 



