THE EVOLUTION OF LIVING BEINGS. 59 



rived from individuals, differing from one another in 

 more than one respect, this hypothesis of an individua- 

 lity of the gametes, maintained unimpaired during the 

 process of fusion, can no longer be upheld, because then 

 the hybrid, sprouting from the zygote, no longer forms 

 but two kinds of gametes, but several kinds, all of 

 which, except two, consequently must necessarily be 

 different from the kinds of gametes, produced by the 

 parents. 



How did this change come about? 



We know nothing about it. 



All so called explanations, all hypotheses of separate 

 bearers of the several characters of the individual, all 

 surmises of so called hereditary units which retain 

 their individuality during nuclear fusion, about in the 

 same way as the chromosomes do, and which, after 

 the opinion of some, form parts of the chromosomes, 

 and, by their interchangability, make new combinati- 

 ons, and consequently formation of a large number of 

 different gametes possible, have their footing in Dar- 

 win's hypothesis of pangenesis, no matter whether we 

 call such units pangens, gens, factors or by any other 

 name. 



Their existence is a mere supposition; the so called 

 fact of the fragmentation or pulverisation of the chro- 

 mosomes during synapsis, held by some to give consi- 

 derable support to their real existence, is in itself far 

 from having been satisfactorily established. 



After all, the chief reason for the making of the hypo- 

 thesis of pangens, is the creed that the smallest particles 

 of living matter must necessarily be living themselves, 



