296 Causes and Course of Organic Evolution 



But of equal im])ortance is the great fact that the varied 

 types of "spore" or "bud" cells in acaryote as well as caryote 

 ])lants and animals are hereditarily somatic cells which by 

 cytological modification per}jetuate and reproduce all of the 

 parental details. Further with evolving chromatin formation, 

 one race of "spore" cells shows varying wavering between 

 ordinary spore or bud multiplication, parthenogenesis, and 

 production of complemental sex cells. When the last is effected 

 reduction by half of the chromatin substance takes place in- 

 each gamete cell preliminary to fusion of the two. 



We conclude then that sexual cells have originated evolu- 

 tionarily from spore cells, that spore cells were derived from 

 and were preceded by somatic cells formed by simple division, 

 and this mode is anticipated and doubtless initiated by that 

 physical process of division or budding which proceeds in many 

 inorganic colloid mixtures, and which causes multi])lication 

 and hereditary perpetuation of inorganic colloid cells. 



How then has progressive extrusion of chromatin substance 

 been effected, and what benefit biologically has been secured 

 by formation of complemental sexual cells? If unicellular or 

 multicellular nucleate plants and animals, or their common 

 ancestors during archsean times, became temporarily exposed 

 as individuals to new and diverse environal states, such might 

 cause amongst one group of these an increase or plus condi- 

 tion in definite tubes of cognitic energy, and correspondingly 

 equal decrease or minus condition in another group. Asso- 

 ciated ^\^th, and possibly even originating such, might be a 

 gradual breaking down and extrusion of definite products 

 with which such increase and decrease were connected. 



Given then a return of both groups to primitive average 

 conditions, the unicellular groups or certain cells of each multi- 

 cellular group, charged each with either a plus or a minus sup- 

 ply of cognitic energy, would undergo fusion. So as compared 

 with long continued exposure of a group of organisms to one 

 set of conditions, temporary exposure of two groups of these 

 organisms to diverse conditions from each other, and from 

 the past environment, and subsequent intermingling of the 



