Mogisclies Centralblatt 



Unter Mitwirkung von 

 Dr. K. Goebel U nd Dr. R. Hertwig 



Professor der Botanik Professor der Zoologie 



in Miinchen, 



herausgegeben von 



Dr, J. Rosenthal 



Prof, der Physiologic in Erlangen. 



Der Abonnementspreis fur 12 Hefte betragt 20 Mark jahrlich. 

 Zu beziehen durch alle Buchhandlungen und Postanstalten. 



Die Herren Mitarbeiter werden ersucht, alle Beitrage aas dem Gesamtgebiete der Botanik 

 an Herrn Prof. Dr. Goebel, Miinchen, Lnjsenstr. 27, Beitrage aas dem Gebiete der Zoologie, 

 vgl. Anatomie uad Entwickelungsgeschichte an Herrn Prof. Dr. R. Hertwig, Miinchen 

 alte Akademie, alle iibrigen an Herrn Prof. Dr. Rosenthal, Erlangen, Physiolog. Institnt 



einsenden zn wollen. 



Bd. XXXIII. SO. Januar 1913. ^Ti" 



I nli alt: East and Hayes, Heterozygosis in Evolution and in Plant Breeding. - Saint-Hilaire, 

 Das Biologiscbe Museum des Zootomischen Institute der Universitat Dorpat. Dewitz, Uber 

 die experimentelle Abandoning von Organismen clurch die ehemische Beeiuflussung ihrer 

 Fortpflanzungskorper. Kriiger, Weitere Mitteilungen zur Kenntnis der Sehlafstellungen 

 bi'i iSiiBwassc-rfischen. Brnil, Beobachtungen iui Kempttbaler Ameisengebiete Robertson. 

 Further Explanatory Remarks Concerning the Normal Rate of Growth of an Individual 

 and its Biochemical Significance. Woodruff, Dreitausend und dreihundert Generationen 

 von Paramaecium ohne Koujugatiou oder kiinstlicbe Reizung. - - Leontowitsch, D&s 

 ,,Syncellium" als dominierende zellulare Struktur des tierischen Organismus. De Vrit-s, 

 Die JIutatioueu in der Erblichkeitslehre. Fischer, Die Nephritis. 



East, E. M. and Hayes, H. K. Heterozygosis in Evolution 



and in Plant Breeding. 



U. S. Dept. Agr., Bur. Plant Industry Bull. 243: 158. 1912. Plates 8. 



This paper is a resume of experiments on the effects of 

 crossbreeding and inbreeding begun in 1906 by the senior author 

 at the Connecticut Agricultural Experiment Station and since 

 prosecuted both there with the aid of the junior author and at 

 Harvard University. The material used was maize, representing a 

 typical cross -fertilized plant, and various species of Nicotiana, 

 representing self-fertilized plants. 



The thesis defended is that 1. the effect of inbreeding is merely 

 an isolation of homozygous types when from natural or artificial 

 cross breeding there has arisen a physiological mixed race, and 

 that 2. the effect of crossbreeding is to bring about greater vigor 

 through a stimulus to development which is the direct effect of 

 characters being present in the heterozygous condition. This stimulus 

 to development is found to be "cumulative up to a limiting point 

 and varies directly with the number of heterozygous factors in the 

 organism, although it is recognized that some of the factors may 

 XXXIII. 1 



