THE HiEMORRHAGIC DIATHESIS 185 



of the haemorrhagic tendency. For instance, the 

 locality and the nature of the injury have some 

 significance. In a few cases, wounds below the neck 

 may not bleed to excess, whereas abrasions of the 

 most trifling description affecting the lips, cheeks, 

 or gums may baffle all attempts to stanch the flow. 

 Again, needle pricks, if small, do not bleed, probably 

 because the elastic skin seals over the opening ; it 

 is even safe to withdraw blood from a vein. Further, 

 it is not true that the haemorrhage never stops. It 

 may cease with or without treatment, sometimes 

 permanently, sometimes only to come on again later. 

 If a subcutaneous haematoma develops, the wall is 

 lined by well-formed clot, but the central portion 

 contains blood which shows no tendency to coagu- 

 lation in spite of the contact with clot. It is the 

 capillaries, rather than the arteries, which continue 

 to ooze. 



It will be a matter of opinion whether under the 

 generic name of haemophilia we should include cases 

 that arise every now and then, in either sex, of a 

 congenital and persistent tendency to bruise and 

 bleed from every slight abrasion, apart from any 

 family history of a similar kind. There is no doubt 

 that the symptoms and course of some of these cases 

 are identical with ordinary haemophilia,* and they 

 are nearly a,s common. Bulloch states that the 

 characteristic joint affections never occur except in 

 the hereditary class. 



* See instances given by Squire, Brit. Med. Jour., 1910, i, 

 p. 1168 ; and Osier, Lancet, 1910, i, p. 1226. 



