ON THE EXPERIMENTAL STUDY OF HEREDITY. 293 
The Experimental Study of Heredity.—Report of the Committee, 
consisting of Dr. Francis DaRwin (Chairman), Mr. A. G. 
TANSLEY (Secretary), and Professors BATESON and KEEBLE. 
THe grant has been used to defray part of the cost of experiments 
carried on by Miss H. R. Saunders, Mr. R. P. Gregory, Miss Gairdner, 
and Miss Sutton. 
The results of several years’ work by Miss Saunders on the 
inheritance of doubling in stocks has been published in the course of 
the year.t The results have shown that in the case of stocks the 
doubling is a character which is inherited in accordance with definite 
laws, and is quite unaffected by the conditions of environment. In 
the case of certain races, it is now possible to formulate the complex 
scheme of gametic segregation which determines the inheritance in a 
given breeding. Certain points concerning the way in which the inherit- 
ance of the double character is bound up with the inheritance of flower- 
colour require further investigation, and the work is being continued 
in the hope of clearing these up. 
The inheritance of doubling in several other genera is also now 
being investigated, but as these plants are mostly biennials, the results 
of the work of the past season will not be obtained until next year. 
Mr. Gregory’s experiments on Primula sinensis have been con- 
tinued and extended. A considerable part of the work has been devoted 
to the further investigation of the special inter-relations between certain 
genetic factors which are exhibited in this species. Reciprocal crosses 
have shown that the gametes of both sexes may constitute series 
exhibiting the remarkably low types of partial ‘coupling’ and 
‘repulsion’ previously reported; these low orders of partial coupling 
cannot therefore be explained, as at one time seemed possible, as being 
due to the existence of special inter-relations between the factors in 
the gametes of one sex only, those of the other sex being unaffected. 
The phenomena of ‘ flaking’ are being investigated more fully. It is 
hoped that results of some interest may be gained from two cases of 
gigantism which are now under investigation; in both cases there is 
evidence that the nuclei differ structurally from those of the giant 
races previously investigated and from those of the ordinary non-giant 
types; in each case, too, a departure from the normal segregation 
appears to be indicated. One of the cases is of special interest in that 
a sister family consisted entirely of non-giant plants, which exhibited 
normal segregation in F,. 
Experiments with the gynandrous variety of the common wall- 
flower show that this variety is recessive to the type. These experiments 
are being continued with the assistance of Miss Gairdner, who is also 
making a study of the morphology of the various gynandrous forms. 
Tropeolum.—Miss Gairdner and Miss Sutton are continuing the 
experiments with Trop@olum, principally with a view to studying the 
inheritance of variegation in the leaves. 
* Journal of Genetics, December 1911. 
