CHAP, iv.] METABOLIC PROCESSES OF THE BODY. 577 



A diabetes of a permanent character, much more closely 

 resembling the disease as occurring naturally, may be brought 

 about in the following remarkable manner. If in a dog (and 

 the same result may be obtained in many other animal* j t he- 

 whole of the pancreas be removed, sugar makes its appearam e, 

 in the urine, and the animal soon becomes emaciated, with all 

 the symptoms of ordinary diabetes. The gland must be 

 removed ; mere ligature or blocking of the duct does not 

 produce the effect. And the whole gland must be removed ; 

 if only a small portion be left, the symptoms do not appear 

 or are slight and temporary. Moreover, it has been found pos- 

 sible to transplant a portion of the gland, removing it from 

 its normal surroundings and grafting it in some other situa- 

 tion. In such a case the whole of the rest of the gland may 

 be removed without causing diabetes ; but the symptoms imme- 

 diately appear if the transplanted portion be subsequently 

 removed. We may infer that the pancreas, besides secreting 

 pancreatic juice, produces some effect on the blood circulating 

 through it, probably discharges into the blood some substance, 

 and that this effect, this substance, has to do with the regula- 

 tion of the sugar in the blood. So long as even a small portion 

 of the gland is left, adequate effect is produced, and sugar does 

 not accumulate in the blood ; but if the whole gland is wanting, 

 then in consequence of the lack of the normal effect, sugar does 

 accumulate in the blood and the condition of diabetes is set up. 

 How this result comes about, whether by reason of a failure 

 to get rid of the sugar which is normally produced or by an 

 abnormal production of sugar, has not yet been clearly made 

 out. The salivary glands, in many respects so like the pan- 

 creas, have no such action. 



The diabetes thus set up by extirpation of the pancreas has 

 further the following resemblance to ordinary diabetes. In 

 mild forms of the natural disease, sugar only makes its appear- 

 ance in the urine when carbohydrate food is taken ; but in sev in- 

 forms a large quantity of sugar may be present in the urine 

 even though no carbohydrate food at all be taken. The suijar 

 in such a case probably comes from the splitting up of pi 

 matter, and this view is supported by the fact that a certain 

 relation may be observed between the sugar and the urea 

 secreted in the urine. So also after extirpation of the pan- 

 creas, especially if some of the pancreas be left behind, a mi hi 

 effect may be produced, in which sugar appears in the urine 

 only after carbohydrate food. On the other hand se\ 

 forms arc also met with in which sugar passes away by the 

 urine, though carbohydrates be rigidly excluded from the food. 



As a sort of converse to diabetes we may mention that the 

 administration of arsenic in sufficient doses or for an adequate 

 time prevents an accumulation of glycogen in the liver and 



37 



