NOTES AND LITERATURE 



HEREDITY 



One of the most important papers relating to heredity that 

 has appeared in recent months is that of Tower, dealing with 

 hybridization investigations with species of the genus Lo.ptino- 



paper, but mention it rather as a means of calling attention to 

 its importance and suggesting that any one interested in theo- 



has done an immense amount of work with this genus. His re- 

 sults lead him to accept the factorial hypothesis as an explana- 

 tion of Mendel ian phenomena but to discard wholly the de 

 Vriesian interpretation of these factors. The most important 

 contribution in this paper is the apparent fact that the environ- 

 ment at the time when eggs are fertilized may change very ma- 

 terially the nature of the hereditary factors. It is unfortunate 

 that the author does not give more details in connection with 



will be seen from the following. In experiment 409, which was 

 several times repeated, the results were exactly as if one of the 

 parents had been a heterozygote between the two species. F 1 con- 

 sisted of two types, one of which was identical with the female 

 parent and the other intermediate between the two. The one 

 like the female parent bred true to that type, while the other 

 behaved in all respects as a heterozygote. In experiment 410 

 the same two species were utilized, but the temperature and 

 humidity conditions at the time the eggs were fertilized were 



