HYBRIDIZATION EXPERIMENTS. 27 
The chickens produced by the matings in No. 2, No. 6, and No. 7 
may be stated to contain jungle and domestic blood in the following 
proportions respectively :— 
No. 2 gives chicks = (J $ + D 8). 
No. 6 is = (J + D 8). 
No. 7 34 =(J}+D). 
It will, in conclusion, be observed that, whereas the hybrid 
cockerels have been fertile with the domestic and with the } domestic 
hens, all the hybrid hens have been apparently sterile. 
It has been therefore asked, Can the hybrid hens be sterile although 
the hybrid cocks are fertile? Does such a condition obtain in 
breeding other birds or animals ? 
No attempt has been made to demonstrate Mendel’s law, the 
experimenters being ignorant of its exact nature. Doubtless 
many very interesting points bearing on this subject have passed 
entirely unnoticed and unrecorded. 
The main object of the present experiments has been to investigate 
the sterility or fertility of the hybrids. The partially negative 
results so far obtained can hardly be said to finally settle the question. 
Experiments on a more extended scale are required. The present 
experiments have nevertheless added somewhat to the meagre 
data upon which the question of sterility of the hybrids was based. 
It is for others to state whether the results obtained so far in any 
way modify, confirm, or refute the accepted opinion that ‘‘ this 
species then may in all probability be rejected as one of the primitive 
stocks of domestic fowl.’’ 
These experiments are greatly crippled for want of funds. The 
cost of putting up several suitable runs by any one experimenter 
is prohibitive, and many who are keenly interested in the experi- 
ments are deterred from undertaking them on the score of expense 
and want of ground space. 
The accompanying diagram ‘gives at a glance the various experi- 
ments and their results up to date (June 1, 1906). 
It will be seen that the jungle and domestic mating is the starting 
or centre point. 
The mating of the domestic male with jungle female gives a 
negative result. That of the jungle male and domestic female 
gives the hybrids, males and females. The hybrid female mated 
back to the jungle cock gives negative results. The mating of 
hybrid with hybrid shows negative results. 
The mating of the hybrid male back with the domestic pared 
gives males and females, which may be called hybrid-domestic 
(or J + 3? D). The female of this, mated back to the hybrid 
