THE GKXKKAL SUiNIKIOANOE OF AMriUMlXIS :233 



sink to ouo kind of id, that is, tli;U the ovnu-plasni m.iy then i-oiisist 

 ontiivly of idontioal ids. If chance variations of certain determinants 

 in UHfavouKvhle directions oecvir in some of the ids eomposiiii:; the 

 i;vnn-plasm, these aiv bivught tooether in tlie ottsprin>;- fixmi lx>th 

 the maternal and the pitermvl side, and will occur in an ineroasing 

 number of ids the lon^ei- tlie inbreeding has o\ine on. that is. the 

 smaller the luintber of ditieivnt ids ha.s become. The unfavourable 

 variation- tendency is therefore persisted in. and its intluence upon 

 the development of a new deseendattt will be the i;roater tlie larger 

 the number of identical ids with these unfavourable variations. It is 

 obvious that the cix^ssino- of an animal, which is thtis, so to speak, 

 dei:,vnei-atin>i' slightly, with a member of an univlated family nmst 

 immevliately have a i;ood etleet upon the descendants, for in this 

 way qxiitt" ditieivnt ids with other variations of their determinants 

 aiv intixxluceii into the inbivd gerni-plasm which had become too 

 monotonous. 



Fivim this tluvivtical interpivtati^vn of the injurious consequences 

 of inbivetling we may at once infer that not every inbreedinsj 

 necessju-ily implies dej^enenition, for the vxvmivnce of unfaNOurablc 

 variational tendencies in tJie. gin-m-plasm is pivsuppi^sed as the 

 startiuij-point of dojjeneration, and if these do not exist thei-e can \x> 

 no liecenCKitiou. This hiirmonires with the fait that the evil etl'eets 

 of inl^-eCilinp, aiv oWervcii to ;■!),»/ j/iwirfi/ «"» amount, and «*<»»/ not 

 fk^-iir at all. But they aiv jrreatest in bivetls ai-tificially sekH"ted 

 by man, which have long lxx?n under unnatural, diivetly influential 

 ixmditions, anvl aiv also ivmovevl fivm the purifying intluence of 

 natural seUx'tion In such cases, theivfoiv. theiv is every prolvibility 

 that divei^e unfavoui'ahle variational tendencies in the determinants 

 will occur. 



But how aiv we to understand tlie fait that ptnv pvrtlienogenesis 

 may last through imtumei-aWe genCKitions. and yet no degenei-ation 

 sets in? 1 believe very simply. In this case too, the sjime ids which 

 weiv }veuliai- to tlie mother of the race aiv contained in the descend- 

 ants, but they do not diminish in number, foi- in piiiv and normal 

 pvrtlieiiogenesis. such as that of C;iji i> ,t'/»f(ii,>. the second maturation- 

 division of the ovum does not take place, and this is pivcisely the 

 nuclear division which eli\x>ts ivdnetion. In addition, the inti\xInctiou 

 of identii-al ids. which nnist take place in the case of inbiveiling 

 at every .-iinphimixis. d. i s not ix^nir, and. what is certainly of great 

 iinpi>rtanoe, all these cases aiv old species, living under natural 

 conditions — the same conditions under which thiy liveil as amphi- 

 gvMiotis species, and not newly formed biveds under aititicial 



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