THE FACTS AND FUNCTION OF SEX 37 



the case of physical characters, also, this principle 

 is constantly illustrated. It is obvious that the 

 principle is explicable in strict accordance with the 

 theory that the function of amphimixis is to ensure 

 stability of the type — that is, be it well noted, the 

 type of the race, not the new and varying parental 

 type.^ Indeed, every kind of evidence, old and new, 

 tends to support this new interpretation of the func- 

 tion of amphimixis. Mr. Reid is surely justified in 

 saying that, " Nothing in nature is more certain than 

 that the function of bi-parental reproduction is to 

 produce regressive variation ; and nothing in science 

 is more remarkable than that, in spite of plain, abun- 

 dant, and conclusive evidence, it should so long have 

 been regarded as the cause of progressive variations." 



Hence it appears that, in every species which is 

 sexually reproduced, there is, on the average, a 

 greater tendency towards reversion than towards 

 progression, a greater tendency to vary towards the 

 ancestry than away from it ; fur the weight of amphi- 

 mixis is always thrown upijn the side of regressive 

 variations, and always tends towards the suppression 

 of progressive variations. Again, to quote frum Mr. 

 Reid : " Under conditions of natural selection, bi- 

 parental reproduction ensures that all [organic] 

 evolution shall be on lines of small variations, not 

 on lines of great abnormalities." 



Mr. Reid has thought this matter out with ex- 

 treme completeness. He observes that bi-parental 

 reproduction occurs invariably in all large and com- 



1 The word type in biology has always a generalised meaning, 

 though in common parlance this proper meaning of the term is fre- 

 quently obscured. 



