378 LOCAL TISSUE REACTIVITY 



lion ol liii^li j)()tcii(y, the hcnioi 1 lia,<i,i( lesions are of eonspic uoiis 

 occurrence, namely, hemorrhagic spots in the skin, l)lee(liii<^s in 

 mucous membranes, etc. This is accompanied by climinution oi 

 blood platelets, vascular damage and thrombosis. Herz (1917) 

 draws attention to the hict that outside of the diminution of the 

 blood platelet count there must exist some other unknown fac- 

 tors. Thus, in cases of hemorrhagic typhoid fever with reduced 

 platelet count reinfections with paratyphoid and typhoid relapses 

 riui a mild course without hemorrhagic complications. 



The Schoenlein-Henoch purpura is a disease in Avhich the con- 

 spicuous symptoms are erythematous, urticarial and edematoirs 

 processes. The urticarial lesions may then, in turn, become hem- 

 orrhagic. The disease unquestionably frequently gives the impres- 

 sion of an infectious disease or intoxication. Fever in repeated 

 attacks occms in some cases. Glanzmann (i9i(3) considers the 

 disease closely allied to anaphylaxis because of the symptoms re- 

 sembling serum sickness. 



Nonthrombocytopenic purpinas without changes in blood 

 platelets (not considering hemophilia, avitaminosis, etc.) may be 

 observed follo^ving numerous infectious diseases such as menin- 

 gococcus meningitis, sepsis, scarlet fever, grippe, dysentery, 

 exanthematous diseases, anthrax, yellow fever, and plague. Ac- 

 cording to Pratt and Morawitz it is possible that in these condi- 

 tions there is no diathesis existing and one is simply dealing with 

 multiple localized injuries to the blood vessel wall induced either 

 by toxins or by bacteria forming emboli such as is observed in 

 meningococcus meningitis. 



From the description of diseases of hemorrhagic diathesis just 

 given, it is obvious that whatever the etiological factor may be, 

 the conspicuous feature is an altered reactivity on the part of 

 the blood vessels ^vith or without changes in the blood platelet 

 count. Whether the latter changes are of only incidental or causal 

 relationship, the -altered reactivity of the blood vessel deserves 

 special consideration. The possible relationship of the disease just 

 described to bacterial or virus infections has always been strongly 

 suggested by many authors. The facts presented in this monograph 

 offer a Avorking hypothesis along these lines. 



As pointed out previously, the striking microscopic alteration 

 of the phenomenon under consideration in this monograph is the 

 hemorrhagic character of the tissue response, and microscopically, 

 this is expressed in severe vascular damage, viz., hemorrhage and 



