334 APPENDIX 



If, furthermore, the several forms of the egg and pollen cells of 

 the hybrids were produced on an average in equal numbers, then 

 in each experiment the said four combinations 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 fertilisa- 

 tion, 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 third experiments 

 and the second 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 B, appear in each union, and 

 are also partly constant and partly in hybrid union with the reces- 

 sive 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 wrinkled and yellow; the fourth 

 is constant in both recessive characters, so that the seeds are 

 wrinkled and green. In both these experiments there were conse- 

 quently four sorts of seed to be expected — viz. round and yellow, 

 round and green, wrinkled and yellow, wrinkled and green. 



The crop fulfilled these expectations perfectly. There were 

 obtained in the 



1st Experiment, 98 exclusively round yellow seeds; 

 3rd " 94 " " " " 



^ [To prove, namely, that both were similarly differentiated, and not one or 

 other only.] 



