Origin of Sexuality 291 



serted that each cell in an organism is a hermaphrodite struc- 

 ture. To tliis thesis many subsequently took exception and 

 with some show of reason perhaps, seeing that no direct proof 

 in indi\'idual cell life was forthcoming. But one is forced 

 to accept its absolute correctness from study even of one hybrid. 

 It is this hermaphroditism of the entire hybrid organism 

 wliich not only impresses on it the structure that the naked 

 eye and microscope reveal, but wliich causes it to have a life 

 cycle whose successive steps are intermediate between the 

 parent extremes. Thus sufficient facts are in our possession 

 and will, we hope, be greatly supplemented ere long to prove 

 that the period of bud-bursting, of leaf -expansion, of flower- 

 production, fruit-ripening, and other vital phenomena in hybrids 

 are all dependent to a wonderfully exact degree on hereditary 

 inheritance." 



This separation of the stereoenergized molecules that are 

 distributed, in definite amounts and directions, during suc- 

 cessive divisions of the chromosomes is suggested by the be- 

 havior of the male and female chromosome constituents, in 

 various plants that have been studied, and whose chromosome 

 constituents fuse by apposition of molecules, rather than blend 

 chemically. But the most direct evidence is got from such 

 studies as those of Haecker on the developing eggs of Cyclops. 

 In these the apposition but continued distinctness of the male 

 and female chromosome constituents could be traced through 

 a great part of the history of each developing animal. 



Again the cases recorded by Sanson {106) for hybrid "Niver- 

 nais" breeds of cattle and many like records in breeders* jour- 

 nals testify to the frequent separation of cell characters derived 

 from one or other parent. 



Since many phenomena of sexuality then are common alike 

 to plants and animals, in the few succeeding pages of this 

 chapter a com})arative review of these j^henomena will be 

 attempted. So many details however still remain obscure 

 or unknown to us that what follows must be regarded merely 

 as a tentative and imperfect presentation of results. 



First: In tracing the gradual evolution of sexuality amongst 

 the simpler algse and fungi it was noted that there is often a 



