346 ABSTRACTS OF PAPERS. [VOL. II. 



by a single spermatozoon observed by Boveri. In such cases 

 the asters in both halves multiply progressively at the same 

 rate, but complete division occurs in only the nucleated half. 

 In the non-nucleated half, however, each aster becomes sur- 

 rounded by a deep constriction which afterwards fades out. 

 This result stands intermediate between those of Boveri and 

 Ziegler. As in the case of the magnesium eggs, an aster un- 

 accompanied by nuclear material forms a division center of the 

 surrounding cytoplasmic area, but is here apparently unable to 

 effect complete division in the absence of chromosomes. 



XIV. EXPERIMENTS UPON THE INFLUENCE OF 



THE SEXUAL CELLS UPON THE 



SOMATIC CELLS. 



GEORGE WILTON FIELD. 



1. Of iJic sexual cells of one individual upon the somatic 

 cells of another individual. 



This is generally held to be a phase of Telegony. Several 

 instances have been cited by Gadow, Nathusius, and Bulman 

 to show that the spermatozoa affect the somatic cells which 

 secrete the eggshell. Thus, the shell of eggs of fowls which 

 normally lay brown eggs are said to become lighter in color 

 when the birds are mated with a male of a breed which lays 

 white eggs ; and conversely, white eggs become brownish, if 

 the birds are mated with a male of a breed which lays 

 brown eggs. 



Our experiments were carried on at the Rhode Island Agri- 

 cultural Experiment Station upon Leghorn pullets (white eggs) 

 mated to a Light Brahma cock, and upon Light Brahma pullets 

 (brown eggs) mated to a Leghorn cock. By means of trap 

 nests the series of eggs laid by each individual was- followed ; 

 no departure from the ordinary normal color of the egg- 

 shell could be observed. 



2. Of the sexual cells upon the somatic cells of the same 

 individual. 



