CHAPTER X 



C ELL MULTIPLICATION AND THE ORIGIN OF 

 SEXUALITY IN PLANTS AND ANIMALS 



Many valuable books, memoirs, and papers have appeared 

 during the past quarter century on the above subject. These 

 have been freely drawn on by the writer, in addition to observ- 

 tions of his o\\ti, in the preparation of the present chapter. 

 In study of the theme, if his methods or conclusions are more 

 or less divergent from results given in the publications referred 

 to, it "^all merely be that he has striven to interpret facts and 

 theories in a manner that will conduce the more to further 

 advance according to his thinking. If he is mistaken in his 

 views, the steady onward march of discovery will gradually 

 demonstrate such. 



The study of sexuality and of sex-evolution is one of the 

 basic requirements of biological progress. For no process 

 in life is more striking and regular to even the casual biological 

 observer. The tangled floating masses of conjugating Spiro- 

 gyra^ the orange-yellow oozing spermatial material on the 

 tips of Fucus thallus, the stellate or umbrelloid growths on 

 the liverworts and mosses, the flower clusters and pollen clouds 

 that appear on exact days often of each year, even though on 

 separate shrubs or trees, are all familiar objects in plant life. 

 Equally also the floating medusoids, the bee or ant flights, 

 the migrations of the salmon and other fishes, the frog-spawn 

 of spring time, the nesting of the birds, and many other equally 

 expected events are seasonal exhibitions of sexual develop- 

 ment, or are prophetic of such. 



Now the marvelous exactness in time relation, shown equally 

 during sex-cell conjugation and spore-dissemination prelim- 

 inary to such conjugation, indicate that definite waves of 

 energy, definite lines of energy, and definite transformations 



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