i^lSEASJiS OF THE URINARY ORGANS. 231 



*' It is probable enough that the exciting cause of diabetes may 

 sometimes lie in the diges^tive organs, as Mr. McGregor supposed. 

 The results of his experiments do not conflict with M. Bernard's. 

 Mr. ]\IcGregor, you may remember, found sugar in the partly- 

 digested food brought up from the stomach of a diabetic patient. 

 He detected it also in the saliva ; and in the feces, which, when 

 allow'ed to dry spontaneously, became covered, after the lapse of 

 aome time, with distinct crystals of sugar. And yeast having been 

 administered to two diabetic patients, in ounce doses, after each 

 meal, had soon to be discontinued, because the patients, to use their 

 >wn expressions, felt as if they * were on the eve of being blown 

 up.' There being sugar in the blood, we need not be surprised 

 that he met with it in the gastric and intestinal secretions from 

 the blood. Dr. Harley has observed that by injecting irritating 

 matters into the portal vein, (ammonia, ether, chloroform, alcohol,) 

 a saccharine condition of the urine may be artificially produced. 

 It is conjectured that these substances act upon fibers of the pueu- 

 mogastric nerve, whence an impression is transmitted to the nerv- 

 ous centers, and thence is again reflected upon the liver through 

 the splanchnic nerves. It is not difficult to imagine that irritat- 

 ing substances may find their way into the portal blood through 

 a faulty digestion, or through the use of certain kinds of food or 

 of medicine. Again : since contrived irritation of the brain at the 

 origin of the pneumogastric nerves will make the urine saccharine, 

 the cause of diabetes in the human subject may reasonably be placed, 

 in some instances, within the skull ; and we may understand how 

 injuries or diseases of the brain, or even mental disquiet and de- 

 jection, operating through the brain, may produce it. Some strik- 

 ing cases have been published by Dr. Goolden, in which head 

 symptoms were accompanied by saccharine urine, and in which 

 the diabetic symptoms were checked or removed by remedies ad- 

 dressed to the head affection — by blisters esi)ecially, and by pur- 

 gatives. Nay, we may ask whether there may not, in fact, be two 

 varieties of diabetes mellitus, in one of which the animal and in 

 the other the vegetable form of sugar may be present in the urine, 

 and whether the one of these varieties may not be more hopeful 

 of cure or recovery than the otlier. Bearing in mind the name 

 and the distribution of the pneumogastric nerve, may we not in- 

 dulge the conjecture that disease or injury of the brain near the 

 (y jin of that nerve may directly affect the functions of the st< m- 



