418 THE HEMORRHAGIC DIATHESES 



and it may not be as yet quite certain, as His assumes, that this is an excli 

 sively maternal formation, still pathology furnishes a number of remarkab 

 facts emphasized by Klebs, which assign to the connective tissue germ (" pari 

 " blasts ") a definite position in the structure and economy of the body. As i 

 the controversy in regard to the origin of the parablasts and their compariso 

 with the archiblastic tissue, no matter how it may be decided. His has prove 

 the entrance of the parablastic endothelia into the cavities of the heart ar 

 the vessels (a view which has been given new support by Kolliker and by ( 

 Hertwig) and this indicates a great advance in pathology. If this speeii 

 position of the parablasts is recognized, quite new view-points are presente 

 for the production of pathologic predispositions during fetal development, i 

 which Klebs particularly refers. For it may be proven that in a varyin 

 development of the connective tissue extraordinarily important congenital an 

 pathological processes are combined, and that these are processes in which tl 

 transmission of both sexes plays throughout a very different role, the femal 

 element representing the carrier of the disturbance, without in all cases pa: 

 ticipating in the disturbance itself, while the male element is the passive par 

 We might be inclined from this general fact to ascribe to the parablasts £ 

 least a predominant feminine nature, as might easily be possible if they actuall 

 arose from leukocytes that had wandered in. As this, however, has not y« 

 been proven we must content ourselves with looking upon the parablast as 

 structure upon which the male pronucleus (sperm cell) in the main has 

 slight influence, much less than the female pronucleus. 



We incline to this view for the reason that individual parts, particularly th 

 bony tissue, by reproducing paternal forms from the parablastic tissues, as i 

 very frequently seen, may be recognized as under the influence of the mal 

 pronucleus. N"evertheless, we may assume that in certain cases this influenc 

 is much less operative in females than in males, and thus the non-appearanc 

 of the disease in the female members of a hereditarily affected family may fini 

 an explanation. 



The same peculiarity of the transmission of properties through the mothei 

 who herself may show no traces of them, is observed (as may be mentioned her 

 in passing) also in other disturbances which cannot be traced exclusively t 

 the parablasts, such as hereditary Daltonism. In this, as in bleeder families 

 the law of transmission to the male descendants is seen, as was mentioned b; 

 Eibot and Darwin. Horner reports two very conclusive ancestral trees, th 

 correctness of which is due to his personal knowledge of the members of th 

 family. The ancestral tree is here given for comparison (Fig. 34). 



This affection occurs exclusively in the male descendants, and is trans 

 mitted by the female who remains free. The single exception of a transmis 

 sion from father to son, which occurred in the fifth generation, is only a] 

 apparent one, for the mother belonged to a collateral line affected with th 

 same defect. It is noteworthy that from this marriage a great number o 

 grandchildren who were color-blind were begotten, the mothers of all, corre 

 spending to the law, remaining unaffected, although in this case the hereditar 

 transmission appears to have attained an unusual development. 



The same law of heredity as in hemophilia and in color-blindness is als 



