NOTES AND LITERATUEE 



HEREDITY 



The Possibility of Inheritance through the Placental Circulation 

 instead of through the Germ Cells. — In the December issue of The 

 American Naturalist reference was made to Professor Bate- 

 son's explanation of the inheritance of haemophilia. Haemo- 

 philia is a tendency to excessive bleeding, ascribed either to 

 "a peculiar frailty of the blood vessels or some peculiarity in the 

 constitution of the blood." It is seen far more often in males 

 than in females, yet the males do not transmit it. Physicians 

 are so confident of this as to recommend that "the daughters 

 should not marry as through them the tendency is propagated. ' ' 



Professor Bateson compared the inheritance of haemophilia 

 with that of the horned condition in sheep. A hornless breed 

 crossed with a horned form yields horned males and hornless 

 females. The latter will transmit horns to their male off- 

 spring only, unless again crossed with horned stock, when horned 

 females will also appear. This analogy with haemophilia holds 

 good in so far as the females transmit a condition which they 

 do not present, and it suggests a possible explanation of the 

 occasional manifestation of haemophilia in females. It fails, 

 however, in an essential point. The horned male sheep transmit 

 their condition whereas the haemophilic males do not. 



A different explanation is suggested by the studies on im- 

 munity reviewed and supplemented by Dr. Theobald Smith. 1 

 Ehrlich, as he states, found that female mice which had been 

 made immune to certain toxic substances gave birth to young 

 which were also somewhat immune. The immunity was soon 

 lost and was never transmitted to the second generation. Im- 

 mune males did not transmit any immunity to their offspring. 

 Other investigators, using rabbits and guinea-pigs, have shown 

 the transmission of several forms of immunity through the 

 females only. 



The artificial immunity may perhaps be permanent in the 

 parent guinea-pigs. It has lasted long enough to affect four lit- 

 ters of one female, and Smith has records of "a considerable 



1 Smith, T. The degree and duration of passive immunity to diphtheria 

 toxin transmitted by immunized female guinea-pigs to their immediate off- 

 spring. Jour, of Med. Eesearch, 1907, vol. 16, pp. 359-379. 



