NUTRITION. 471 



a nonazotized part, giycogen. On this view the more severe 

 form of diabetes would be due to an increased activity of a 

 normal proteid-decomposing function of the hepatic cells; and 

 sometimes the urea and sugar in the urine of diabetics rise 

 and fall together, thus seeming to indicate a community of 

 origin. Diabetes dependent on carbohydrate food might be 

 produced in several ways. The liver-cells might cease to 

 stop the sugar and, letting it all pass on into the general cir- 

 culation, suffer it to rise to such a percentage in the blood 

 after a meal, that it attained the proportion in which the 

 kidneys pass it out; or the tissues might cease to use their 

 natural amount of sugar, and this, sent on steadily out of the 

 liver, at last rise in the blood to the point of excretion. Or 

 the liver might transform (into glucose) and pass on its giy- 

 cogen faster than the other tissues used it, and so diabetes 

 might arise; but this would only be temporary, lasting until 

 the liver stock was used up by the rapid conversion. Arti- 

 ficially we can, in fact, produce diabetes in several of these 

 ways; curari poisoning, for example, paralyzing the motor 

 nerves, makes the skeletal muscles lie completely at rest, and 

 so diminishes the giycogen consumption of the Body and pro- 

 duces diabetes. Carbon-monoxide poisoning produces dia- 

 betes also, .presumably by checking bodily oxidation. Fi- 

 nally, pricking a certain spot in the medulla oblongata causes 

 a temporary diabetes. This might conceivably be due to the 

 fact that the operation injures that part of the vaso-motor 

 centre which controls the muscular coat of the hepatic artery, 

 and this artery, then dilating, carries so much blood through 

 the liver that an excess of giycogen is carried off by the 

 hepatic veins; and in favor of this opinion is the fact that if 

 the splanchnic nerves be cut the whole arteries of the ab- 

 dominal viscera dilate no diabetes follows. This has been 

 explained as due to the fact that so many vessels are dilated 

 that a great part of the blood of the Body accumulates in 

 them, and there is in consequence no noticeably increased 

 flow through the liver. Others, however, maintain that the 

 "piqiire " diabetes (as that due to pricking the medulla is 

 called) is due to irritation of trophic nerve-fibres originating 

 there, and governing the rate at which the liver-cells produce 

 giycogen or convert it into glucose. This latter view, 

 though perhaps the less commonly accepted, is probably the 

 more correct. The hepatic cells do not merely hold back 



