SYMPTOMS AND CLINICAL COURSE 119 



(a) A hereditary group, 



(6) A group occurring in connection with acute diseases, 



(c) The group of cases which appear after psychical irritation, 



(d) A group of cases in which the causes are various or quite un- 

 known. 



The hereditary form has been observed only in isolated instances, but a 

 few times in an extraordinarily striking way. The most remarkable series of 

 observations we owe to Weil. He found 23 diabetics among 91 members of 

 a family which embraced 4 generations, namely, the ancestor, 3 children, 7 

 grandchildren, and 12 great-grandchildren; the heredity was always a direct 

 one, never skipping a generation; men and women were affected to a similar 

 extent. Undue thirst was noted in some of these individuals even as nurs- 

 lings ; besides the breast-milk, it was necessary to administer water ; in others 

 the condition first arose between the second and fourth years of life. Almost 

 all members of the family possessed a good constitution and enjoyed good 

 health; many reached extreme old age. 



There are also other records of the occurrence of diabetes insipidus in three 

 or four successive generations, the individuals remaining mentally and phys- 

 ically healthy, apart from the anomaly in question. 



With comparative frequency, i. e., in about 10 per cent, of all eases, dia- 

 betes insipidus appears after acute infectious diseases (scarlatina, measles, 

 diphtheria, malaria, rheumatic fever, etc.) ; most of these cases (like those 

 just discussed) appeared to cause but slight disturbance of health. They are 

 of theoretic interest from the fact that convalescence in these same infectious 

 diseases is quite commonly associated with an increase in the excretion of 

 urine. It appears therefore that permanent polyuria may arise from a nor- 

 mal transitory polyuria, just as it does in hysterical individuals who have 

 paroxysms with urina spastica. Similarly, permanent polyuria may appear 

 after the temporary employment of diuretic remedies which cause a powerful 

 diuresis. 



In a number of cases diabetes insipidus has occurred as a sequel of vari- 

 ous deleterious factors; extreme cold or heat and sunstrohe are mentioned as 

 causes. More frequently alcoholic excesses, bodily injuries (excluding head 

 injuries), and psychical trauma are mentioned. 



We include this entire group with the idiopathic form of diabetes. But in 

 many cases doubt may arise whether they might not be grouped as well, or 

 better, with hysteria. Even if none of the definite stigmata of hysteria is 

 found, and if the course of the affection does not decidedly favor this diag- 

 nosis, we often meet with striking proofs that the patients belong to the 

 category of neuropathic individuals. They react in this peculiar way to rela- 

 tively feeble irritations which in the normal individual would be without effect, 

 and, when once produced, the abnormal activity of the kidneys continues for 

 a long time. We often succeed in discovering from the history that certain 

 abnormalities have preceded these pathological reactions. Griffouilleres points 

 to the fact that in youth enuresis nocturna has often preceded the condition. 

 Numerous therapeutic experiments lead us to suspect that the neuropathic 

 element plays a prominent role in the etiology of these forms of diabetes. 



