458 THE HEMORRHAGIC DIATHESES 



accepted by me has been exceeded by other authors (e. g., Schwimmer and 

 Scheby-Buch) who are not satisfied with the inclusion of the various forms of 

 purpura, but desire also to include scurvy in this clinical group ; other authors 

 even add hemophilia. 



Apart from the facts demonstrated by bacteriology, which it is hoped will 

 be more certainly confirmed in the near future, purpura is an affection due 

 to the action of unknown deleterious agents, occurring sporadically and show- 

 ing a transitory tendency to different varieties of hemorrhage. In contrast 

 to hemophilia there is no congenital or hereditary factor, and, unlike scurvy, 

 there is no tendency to epidemiologic and endemiologic distribution, and the 

 hemorrhages are not associated with severe constitutional manifestations. 

 Scurvy is distinguished by the fact that it not only occurs sporadically but also 

 epidemically or endemically. More characteristic, however, is its dependence 

 upon external conditions; it is almost invariably the expression of severe 

 nutritive disturbance produced by obscure diseases or by the long continuance 

 of insufficient or improper food. 



Morbus maculosus Werlhofii differs essentially from hemophilia in the 

 fact that it unquestionably belongs to the acquired diseases, in which the 

 factor of heredity is never operative. It has no congenital characteristics, 

 such as are so peculiar to hemophilia. 



This is also a distinguishing factor between scurvy and hemophilia. Un- 

 like the scorbutic patient, the bleeder is frequently well nourished and strong. 

 Except in his tendency to spontaneous hemorrhage he may be looked upon as 

 quite normal. In the comparison of hemophilia with related diseases in the 

 group of the hemorrhagic diatheses, one peculiarity of hemophilia is particu- 

 larly prominent; it is not a pathologic process, but a permanent condition 

 which manifests itself sometimes in consequence of known, at other times of 

 unknown, causes. 



In accordance with these views, we shall consider the purpuric affections 

 together, but we shall not forget the older clinical divisions; we shall bear in 

 mind that between the individual forms of the disease transitional stages 

 occur, and that the barriers between them are artificial. 



The conception of purpura as a particular chapter of special pathology pre- 

 supposes the exclusion of all the affections which are combined with hemor- 

 rhages of the skin, which hemorrhages, however, prove nothing essential or 

 definite, but are only a single symptom in the entire picture. Among such 

 affections are : Hemorrhagic variola, typhoid, acute atrophy of the liver, phos- 

 phorus poisoning, sepsis, ulcerative endocarditis, pernicious anemia, leukemia, 

 yellow fever, icterus gravis, snake-bite poisoning, etc. 



Purpura should be differentiated only when the hemorrhages exist alone 

 or dominate the entire clinical picture. Of course, in investigating the disease, 

 a sequel, such as the resulting anemia, is of minor importance. 



ETIOLOGY 



In most cases it is impossible to determine any immediate cause for the 

 disease; the affection appears in typical cases spontaneously. Cases of this 

 kind have led to the belief that scurvy, which may arise under similar condi- 



