REPORT OF THE CONFERENCE ON GENETICS. 47 
Darbishire, A. D. “Professor Lang’s Breeding Experiments with 
Helix hortensis and H. nemoralis: an Abstract and Review.” Journal of 
Conchology. July 1905. 
* %* 3 xk # 
Exuisit or Waurzinc Mice py A. Darsisuire, of the Royal College 
of Science. This is referred to in~his paper, which will be found 
further on. 
Exureits oF PrimunAs, Bryony, Sweet PrEAs, AND THE Comps 
or Fowns spy W. Bateson, F.R.S., R. P. Gregory, anp 
R. C. PuNNETT. 
Some seedling Primulas were exhibited by Mr. Bateson and Mr. 
Gregory, illustrating that in one dozen plants there are nine palm-leaved 
- (dominant) and three fern-leayed (recessive). This proportion appeared 
in the F, (second generation) from a cross effected between the types. 
It may be remarked that the fern-leaved type (recessive) breeds true. 
On the subject of inheritance of sex some plants of PBryonia alba 
and B. dioica were shown to illustrate and confirm the experiments of 
Correns. Bryonia alba is monecious and B. dioica is dicecious. Between 
these species reciprocal crosses give dissimilar results. B. alba? x« B. 
dioica S gives #’s and ¢’s in equal numbers, but B. dioica 2? x B. 
alba @ gives only plants which are ? except for rare ¢ flowers at the 
bases of the stems. All these hybrids so far have been totally sterile. 
The rules of heredity were further illustrated by Mr. Bateson and 
Mr. Punnett in an elaborate series of experiments on the sweet pea. 
White sweet peas when “selfed’’ breed true. When, however, a cross is 
made between certain strains of whites, all the offspring are purple; such 
purples on “selfing ”’ give purples, reds, and whites in the proportions of 
27: 9: 28. On raising a subsequent generation from these F, plants, 
the twenty-seven purples are found to consist of four different kinds, 
namely— 
(a) Those giving purples, reds, and whites, sixteen in number. 
(b) Those giving purples and whites, eight in number. 
(c) Those giving purples and red, two in number. 
(d) Those giving purples only, one in number. 
Similarly among the nine reds there were :— 
(a) Hight giving red and whites. 
(b) One giving reds only. 
(These reds never give a purple, and the whites always breed true.) 
The chance of a pure purple coming in the F,, (second) generation is 
therefore 1 in 27, and of a pure red is 1in 9. Moreover the composition 
of each plant is shown by its offspring. Consequently, by saving from 
individuals which are thus proved to be pure, these types may at once be 
fixed. 
A curious case of reversion was illustrated in a cross between ‘ White 
Cupid’ (round pollen), a dwarf plant of procumbent habit, and ‘ White 
Bush’ (long pollen), a variety growing 3 feet high. The hybrid was 
