146 Heredity and Eiii^eiiics 



sioii can be obtained in i'»roperl\- guarded experiments and 

 rej^roduced at will, can the ])rocess be admitted as a true 

 evolutionary process. 



The problem, therefore, is to produce "somatic variations" 

 in a soma at such a time, or in such a fashion, that the germ 

 cells will not be affected by the action of the incident forces 

 used, and then b)' breeding discover if the change appears in 

 the progeny arising from the unstimulated germs. Evi- 

 dence of somatic intluence upon germinal material may also 

 be obtained b}' transi)lanting germ glands, especiall}' ovaries, 

 into different somas, as has been done by several experi- 

 menters.' 



The recent experiments of Guthrie,' Castle,-* and Daven- 

 port^ are well adapted to showing any possible action of the 

 soma upon the germ. In Guthrie's experiments proper 

 care was apparenth' not taken to determine the character 

 of the stocks used and to preclude the possibility of regener- 

 ated ovaries. Therefore his results are not conclusive. 

 Guthrie describes his experiments in the ingrafting of ovaries 

 between >'oung females of single-combed black and single- 

 combed white leghorns, as follows: 



During the summer of 1904 I exchanged the ovaries between two 

 black and two white leghorn pullets, weighing about 650 gms. each. 

 One black and one white pullet were saved for controls. All did well 

 for some time after the "perations, but during the winter, before the 

 kuing season began, their condition became extremely poor, owing 

 largely to being kept in inappropriate ciuarters. 



' Castle has recently gi\'en a eomprehensive resume of the ingrafting of germ 

 glands to which reference should be made for more detailed consideration. W. E. 

 Castle and J. C. i'hillips, On Germinal Transplantation in Vertebrates, Carnegie 

 Institution of Washinglim, Nn. 144, Kin. 



- C. G. (luthrie, " I'lirther Results of Trans[:)Uintation of 0\'aries in Chickens," 

 Jour. Exp. Z(^[v/., \' (1008). 



3 Itiid., 1911. 



' C. B. Davenport, Proc. Soc. Exp. Biol, and Med., VII (1910), 168. 



