246 DISTURBANCES OF CIRCULATION 



of this peculiar tendency to prolonged bleeding from insignificant 

 or perhaps imperceptible wounds has been sought vigorously by 

 both histological and chemical means, but as yet without avail. 

 Various observers have described abnormal thinness, or increased 

 cellularity or fatty degeneration of the vessel-walls, but the 

 findings have been far too inconstant to afford a satisfactory 

 anatomical explanation of all the features of hemophilia. Like- 

 wise increased blood pressure can be ruled out, for although the 

 left heart is frequently enlarged, there is usually no increased 

 blood pressure demonstrable ; furthermore, conditions of high 

 blood pressure, such as nephritis, do not cause hemophilia. The 

 theory of " hydremic plethora " is also without good foundation. 



The most natural place to look for the fundamental fault is 

 in the blood, but speaking strongly against this is the frequent 

 occurrence of " local " hemophilia ; e. g., in this type of hemo- 

 philia wounds of the skin may behave as in normal individuals, 

 whereas any injury of the mucous surfaces is followed by pro- 

 nounced hemophilic bleeding ; l in other cases the hemophilic 

 bleeding is limited to regions above the shoulders ; in still 

 another class the bleeding is always from one organ, e. g., the 

 kidneys. Nevertheless, a great deal of investigation of the blood 

 has been done, chiefly with negative results. There are no 

 characteristic changes in the cellular elements of the blood, 

 beyond the changes common to all secondary anemias, except- 

 ing possibly a decrease in the number of white corpuscles with 

 a relative increase in the number of lymphocytes as observed by 

 Sahli. No constant alterations in the salts of the blood have 

 been found ; and the proportion of water, the alkalinity, and the 

 osmotic pressure of the serum all seem to be normal. Since 

 bleeding is normally stopped principally by coagulation, a 

 deficiency in fibrin or its antecedents might be expected, but 

 most studies on this point have shown a normal amount of 

 fibrinogen in the blood of hemophilics, the frequent formation of 

 large tumors of clotted blood at the bleeding points supporting 

 the experimental evidence that the blood contains an abundance 

 of fibrinogen. As to the rate of clotting, the results obtained 

 by different observers are by no means in accord, which seems 

 to be explained by the recent studies of Sahli, 2 who has avoided 

 a number of errors made in earlier investigations. He found 

 that in the intervals between the attacks of hemorrhage the rate 

 of the coagulation of the blood is constantly much slower than 

 normal. During an attack of bleeding the coagulation time 

 approaches the normal ; indeed, it may be faster than normal ; 



1 Abderhalden, Ziegler's Beitr., 1904 (35), 213. 2 Loc. tit. 



