Vererbung, Variation, Mutation. 89 



das Verhalten der Samen der veränderten Halme zeigt. Da die begrannten (also Ghh) 

 Halme der heterozygoten (also GHh) Pflanze die Begrannung konstant weitervererben, 

 muß der Hemmungsfaktor H ausgefallen oder inaktiv geworden sein. Spontaner Weg- 

 fall einer Anlage bei der Geschlechtszellenbildung war für Getreide von Nilsson-Ehle 

 mitgeteilt worden, in den P' r vi wir th sehen Versuchen dagegen würde es sich um eine 

 „vegetative Bastardspaltung" handeln; eine solche Avar von Fruwirth für Lupinus 

 luteus festgestellt worden, doch handelte es sich in diesem Falle um eine Modifika- 

 tion, die nicht weiter vererbt wurde. M. Daiber (Zürich). 



213) Gilbert, A.W. (Ithaca, N.-Y., Cornell Univ.), Suggestive Laboratory Exer- 

 cises for a Course in Plant Breeding. In: Amer. Breeders' Mag. Vol. ü, S. 196 

 —212, 1911. 



A detailed outline of the laboratory practice given in the author's course in plant 

 breeding for agricultural students. Pearl (Orono). 



214) Halsted, B. D. C. (New Brunswick, N. J., N. J. Agr. Expt. Stat.), Geometrical 

 Figures in Plant Breeding. In: Amer. Breeders' Mag. Vol. II, S. 217—220, 1911. 



An account of a scheme for the graphical representation of Mendelian data. 



Pearl (Orono). 



215) Hill, A.W. (Kew, Botanic Garden), The History of Primula obconica Hance, 

 under cultivation, with some remarks on the history of P. Sinensis. 

 In: Journ. of Genetics II 1, S. 1—20, 2 plates, 1912. 



P. obconica ^^as introduced from W. China into England in 1879. For about 

 fifteen years after its introduction it varied little; then considerable Variation began to 

 appear in the colour and size of the flowers, shape of petals and other characters. The 

 history of each Variation is given as far as the author has been able to discover it. 

 Althongh numerous attempts have been made to hybridize P. obconica with other 

 species, and although the evidence on the matter is conflicting, it appears almost certain 

 that the numerous very distinct forms now in cultivation have arisen by selection and 

 crossing of varieties within the species, and not by hybridization with other sijecies. 

 The probably analogous origin of the cultivated forms of P. sinensis is discussed in 

 connexiou with the more recent and better-known historj^ of P. obconica. 



Doncaster (Cambridge). 



216) Laskl, H. I., A Mendelian View of Racial Heredity. In : Biometrika^ Vol. VIII,. 

 No. 3—4, S. 424—430, 1912 



Criticism of Salaman's paper in Journ. Genetics I, S. 273. 



Doncaster (Cambridge). 



217) Pearl, Raymoud, The Personal Equation in Breeding Experi- 

 ments Involving Certain Characters of Malze. In: Biol. Bull. XXI^ 

 Nr. 6, S. 339—366, November 1911, 12 tables, 5 figs. 



1. The observed F.^ Mendelian ratlos determlned from the same four ears 

 of malze by fifteen competent observers all dlffer from one another. 2. The 

 fallure of all observers to agree In thelr dlstrlbution of kerneis Into several cate- 

 gories results from two causes: vlz., (a) the exlstence of somatlcally interraedlate 

 kerneis, and (h) the personal blas or Idiosyncracy of the observer. 3. The mag- 

 nitude of the differences between the several observers Is such as to demonstrate 

 that the personal equation is a factor whlch cannot safely be neglected in work 

 of thls character. 4. The observers who have had most experlence In the appre- 

 clatlon and measurement of Variation have the smallest personal equatlons on the 

 class of materlal and the problem here treated. 5. There Is no evidence that the 

 progeny of somatlcally Intermedlate kerneis Is dlfferent, in any respect whatsoever, 

 from the progeny of dlstlnctly non-lntermedlate kerneis of the same gametlc Con- 

 stitution. — The essentlal polnt brought out by thls study Is, It seems to me, 

 that the well known general fact that every datum of sclence is a functlon (In 

 the mathematlcal sense) of two variables, namely, the observer and the thlng ob- 

 served, is once more emphaslzed by a partlcular case. LlUle (Chicago). 



