SYMPTOMS AND CLINICAL COURSE 115 



therefore quite plain that this cerebral form of diabetes insipidus is intimately 

 related to diabetes mellitus. 



But even in the non-cerebral eases of diabetes insipidus we can often recog- 

 nize a relationship to_ saccharin diabetes, especially when we note the transi- 

 tion from the one disease to' the other, and the occurrence of both diseases in 

 members of the same family. Typical examples of such occurrence have been 

 collected, particularly by Senator, and to these he has added cases observed by 

 himself. It is quite probable that in these instances the neuropathic constitu- 

 tion represents the connecting link. 



The results of animal experiments also suggest the possibility of a rela- 

 tion between diabetes insipidus and diabetes mellitus. During increased (ex- 

 periment) diuresis, no matter whether it is due to drugs or to a simple injec- 

 tion of water, sugar is often found in the urine. Probably the sugar is simply 

 swept along with the current. In man no well-attested examples of this purely 

 secondary appearance of sugar in permanent polyuria have been observed, and 

 the attempts to produce alimentary glycosuria in diabetes insipidus by an 

 increased ingestion of sugar do not favor the view that such a washing out of 

 sugar occurs readily in this disease. 



As we go on from this sketch of the disease to the special varieties of the 

 malady and their course, simple polyuria in cerebral diseases must be first 

 considered. 



This combination is not frequent; about 80 cases may be collected from 

 literature. They are connected most often with injuries to the head ; secondly 

 with brain tumors, then with softening, while the rest are divided among 

 various other cerebral afEections, hemorrhage, encephalitis, meningitis, etc. 



In the overwhelming majority of cases, the lesion is found to be in the 

 posterior parts of the brain, mostly in the region of the pons or the fourth 

 ventricle, i. e., especially in, or at least in the vicinity of, the area in which 

 Claude Bernard and Eckhard were able, by experimental lesions, to produce 

 in animals transitory, and Kahler permanent, polyuria. Kahler collected 

 from literature 25 cases after trauma to the head, and 21 following other cere- 

 bral diseases, and added one of each variety from his own observations ; among 

 the 22 cases of the second group, 4 occurred in disease of the pons, 2 from 

 compression of the pons, 2 from compression of the sinus rhomboidalis by 

 tumor, 3 in diffuse disease of the medulla oblongata; 1 was probably due to 

 a lesion of the medulla oblongata, 1 to a cerebellar tumor, 2 to syphilis of the 

 brain, and 7 to disease of the corpora quadrigemina. 



Less frequently, in cases of trauma to the head, the region of the sinus 

 rhomboidalis is found to be the seat of the lesion ; the description in the few 

 necropsies is not clear. On the other hand, in all of these eight cases there 

 occurred other cerebral symptoms (particularly paralysis of the abducens) 

 which point with great likelihood to a lesion in the pons. 



Hence, although diabetes insipidus is found especially in those cerebral 

 diseases which affect the medulla oblongata, the pons, or the middle brain, 

 nevertheless, upon accurate investigation of the individual observations, we 

 find no single area in the brain which has been uniformly affected, and, on 



