Nabours: Promises and Limitations of Eugenics 



28; 



TWIN LAMBS, BUT DIFFERENT IN COLOR 



Figure 12. The sire of these lambs was a black hybrid produced by crossing a Karakul 

 ram with a Cotswold ev/e, similar to the mother of the lambs. This illustrates Mendelian 

 segregation of characters, as the black and white color- factors have not blended, but have 

 remained distinct. If mated with white animals all the offspring of the white lamb would 

 be white, while half of the black lamb's offspring would be black and the other half white. 



and placed it in the uterus of the 

 short-haired, gray Belgian hare. The 

 Belgian hare than gave birth to a 

 typical long-haired, white Angora rab- 

 bit, without the slightest resemblance 

 of the Belgian breed. The Belgian 

 hare to whose uterus the egg had been 

 transplanted had been only the foster 

 mother, having influenced the fetus, 

 even in these most intimate of rela- 

 tions, not at all. 



Castle and Phil'ips performed, in 

 this connection, a very significant ex- 

 periment using guinea pigs. It may 

 best be descril)ed in Castle's words : 



A female albino guinea pig just attain- 

 ing sexual maturity was by an operation 

 deprived of its ovaries, and instead of the 

 removed ovaries there was introduced into 

 her body the ovaries of a young black 

 female guinea pig. not yet sexually mature. 



aged about three weeks. The grafted animal 

 was now mated with a male albino guinea 

 pig. From numerous experiments with 

 albino guinea pigs it may be stated em- 

 phatically that normal Albinos mated to- 

 gether, without exception, produce only 

 albino young, and the presumption is 

 strong, therefore, that had this female not 

 been operated on she would have done the 

 same. She produced, however, by the 

 albino male three litters of young, which 

 together consisted of six individuals, all 

 black. The first litter of young was pro- 

 duced about six months after the operation, 

 the last about one year. The transplanted 

 ovarian tissue must have remained in its 

 new environment therefore from four to 

 ten months before the eggs attained full 

 growth and were discharged ; ample time, it 

 would seem, for the influence of a foreign 

 body upon the inheritance to show itself 

 were such influence possible. 



Another similar ex|)eriment has 

 been jierformed in |)0uUry by Daven- 



