14 THE DEVELOPMENT OF EAW COTTON 



components ; we may safely presume that both these com- 

 ponents had originally consisted of several elementary 

 species, so that the pedigree of a modern variety of 

 Egyptian cotton is a very complex one. 



The origin of these elementary species has taken place in 

 the same way as for the subspecies and species namely, by 

 abnormal germ-cell formation. The modern view tends more 

 and more towards a physico-chemical conception of living 

 organisms, and in the case of species formation it is being 

 more generally accepted that a new species arises from its 

 parent species at a single jump. Instead of forming its germ 

 cells by symmetrical cell division, so that the offspring result- 

 ing from reunion of male and female cells exactly resemble the 

 parent, something goes wrong with the physico-chemical 

 machinery of cell division, and abnormal asymmetrical pairs 

 of germ cells are formed, with the result that, on fusing with 

 one of the opposite sex, a representative of a new species, 

 subspecies, or elementary species, is produced. The process of 

 sudden origination of new forms in this way is called " muta- 

 tion." The proof of its occurrence demands most careful 

 experimentation, and, as we mentioned formerly, it will be 

 years before such proof can be obtained clearly in the par- 

 ticular case of the cotton-plant, though it may well be still 

 taking place. 



Except for the purpose of clarifying ideas upon the 



subject, it is of little immediate use to discuss elementary 



species in the cultivated cottons, since none 



Natural are recO g n i za bi e . This is due to the fact 

 Crossing. 



that free intercrossing takes platfe under 



natural conditions between related forms of cotton. 

 The Indian group does not appear to cross with the 

 Upland or Peruvian groups, but the two latter can easily 



