No. 562 1 



SHORTER ARTICLES AND REPORTS 



039 



cross the F t plants were also nearly all sterile, but from a large 

 number of crosses a few seeds were obtained and the F 3 and suc- 

 ceeding generations were quite fertile. A very similar result 

 was reported by M. Bellair in the ease of certain tobacco hybrids. 

 It is possible that these investigations may point the way to a 

 better understanding of sterility in species crosses. 



The communication of M. Boeuf on the stability and variation 

 of characters in pure strains of cereals points again to the con- 

 clusion that selection within a ' ' pure line ' ' is without effect. The 

 author cites a large number of experiments to support his thesis. 



The observations of Dr. Trabut upon the origin of cultivated 

 oats will be of interest to students in this field. 



Two papers deal strictly with the inheritance of quantitative 

 characters, a subject of so much interest at the present time. Pro- 

 fessor Bruce, of London, concludes that "It can not be affirmed 

 with certainty that Mendelian laws apply to such characters." 

 Professor Balls, of Egypt, presents a large amount of interesting 

 data regarding quantitative characters in cotton hybrids. How- 

 ever, he believes the fluctuating variations are so large and due 

 to so many causes that it is not possible to show that such char- 

 acters are controlled by segregating factors. The rapid advance 

 in this field of genetics within the past year would hardly sup- 

 port these conclusions. 



An important paper by Nilsson-Ehle on Mendelism and acclima- 

 tization gives us a somewhat different view of arrliniati/ati"!) than 

 that usually held. This author holds that increased resistance to 

 cold, for example, is not obtained by the simple isolation of a 

 more resistant type already present in a variety. Further such 

 types do not arise by mutations in the ordinary sense of the 

 word. He says in his summary (p. 156) : 



On the contrary, all my researches tend to show that the numerous 

 types which can be distinguished, both in the characters of resistance to 

 cold, precocity, and other quantitative characters, are produced by vari- 

 ous combinations of certain Mendelian factors. 



To those biologists who are still skeptical as to the validity of 

 the factorial concept as a means of interpreting the facts of 

 heredity we would recommend the paper by Professor von 

 Tschermak. In experiments on the recrossing of hybrid peas 

 which have extended over eight years and in which "some thou- 

 sands of individuals have been recorded" he is able to "con- 



