358 Mendel's Experiments 



3. The egg cells AB with the pollen cells AB, Ab y 

 aB, ab. 



4. The egg cells ab with the pollen cells AB, Ab, 

 aB, ab. . 



From each of these experiments there could then result 

 only the following forms : 



1. AB, ABb, AaB, AaBb. 



2. AaBb, Aab, aBb, ab. 



3. AB, ABb, AaB, AaBb. 



4. AaBb, Aab, aBb, ab. 



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 fertilisation, even in normal 

 cases, some egg cells remain undeveloped or subsequently 

 die, and ma-ny even of the well-formed seeds fail to ger- 

 minate 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 recessive characters a and b, for which 

 reason they must impress their peculiarity upon the whole 



* [To prove, namely, that both were similarly differentiated, and not 

 one or other only.] 



