630 



THE AMEBIC AN NATURALIST [Vol. XLVII 



V c are located side by side in the same chromosomes not only at 

 the time of the reduction division but also in all nuclear divi- 

 sions and even perhaps that they remain in fairly close prox- 

 imity in the more diffused chromatin of the resting nucleus. 

 Then if homologous chromosomes or their chromatin masses are 

 not closely associated in somatic cells, it would seem possible that 

 whatever causes the change of a V p factor into an S p factor 

 might at the same time affect the V c factor of the same chromo- 

 some changing it into an S c factor, while the V p and V c factors 

 of the homologous chromosome remain unchanged. 



It is of course recognized that a rather formidable number of 

 hypotheses, with subsidiary assumptions, have been marshalled 

 here to account for what may be very simple phenomena, but, 

 if they do not do too great violence to the known facts of cytol- 

 ogy, we are justifiable in accepting them tentatively as an 

 attempt at a consistent interpretation of what otherwise seem 

 inconsistent genetic facts. 



E. A. Emerson 



University of Nebraska 



THE FOURTH INTERNATIONAL GENETICS 

 CONFERENCE 1 



In a subject developing so rapidly as that of genetics, the 

 delay of one and one half years in the publication of the results 

 of an investigation is a serious matter. It is therefore to be 

 regretted that the publication of the proceedings of the Fourth 

 International Conference on Genetics has followed the common 

 fault of international congresses in this respect. In many cases 

 results which were new at the time of the conference have been 

 anticipated by other work. In other cases the results of later 

 experiments have no doubt served to modify opinions expressed 

 at the conference. A portion of this delay is inherent in the 

 nature of an international meeting. However, it is hoped that 

 for the coming conference, steps will be taken to insure the more 

 r.'!|'i<l publication of the proceedings. 



The present volume of 570 pages consists of two parts. Part 

 I (pages 1 to 79) contains the matter of historical interest relat- 



i"Comptes Rendus et Rapports de IV* Conference Internationale de 

 Genetique." Edites par Ph. de Yilmorin. x + 571 pp. Masson et Cie, 

 Paris. 1913. 



