in Hybridisation 69 



should stand in the same ratio to each other. A perfect 

 agreement in the numerical relations was, however, not to 

 be expected, since in each fertilisation, even in normal 

 cases, some egg cells remain undeveloped or subsequently 

 die, and many even of the well-formed seeds fail to 

 germinate when sown. The above assumption is also 

 limited in so far that, while it demands the formation of 

 an equal number of the various sorts of egg and pollen 

 cells, it does not require that this should apply to each 

 separate hybrid with mathematical exactness. 



The first and second experiments had primarily the 

 object of proving the composition of the hybrid egg cells, 

 while the third and fourth experiments were to decide that of 

 the pollen cells*. As is shown by the above demonstration 

 the first and second experiments and the third and fourth 

 experiments should produce precisely the same combinations, 

 and even in the second year the result should be partially 

 visible in the form and colour of the artificially fertilised 

 seed. In the first and third experiments the dominant 

 characters of form and colour, A and It, appear in each 

 union, and are also partly constant and partly in hybrid 

 union with the recessive characters a and b, for which 

 reason they must impress their peculiarity upon the whole 

 of the seeds. All seeds should therefore appear round and 

 yellow, if the theory be justified. In the second and fourth 

 experiments, on the other hand, one union is hybrid in 

 form and in colour, and consequently the seeds are round 

 and yellow ; another is hybrid in form, but constant in the 

 recessive character of colour, whence the seeds are round 

 and green ; the third is constant in the recessive character 

 of form but hybrid in colour, consequently the seeds are 



* [To prove, namely, that both were similarly differentiated, and 

 not one or other only.] 



