284 



I 



CHAPTEE XXXVI. 



VAEiATioisr OF pla:n"ts and animals under domestication 



VIEWED AS BEARING ON THE ORIGIN OF SPECIES. 



DOMESTIC RACES, irO"U^EVER DIVERGENT, BREED FREELY TOGETHER REMOTE 



ANTIQUITY OF SOME ARTIFICIAEEY FORMED RACES SELECTION, BOTH UNCON- 

 SCIOUS AND METHODICAL, VERY INFLUENTIAL IN FORMING NEW RACES 



THE CHARACTERS OF SOME RACES OF THE DOMESTICATED PIGEON OF GENERIC 

 VALUE REVIVAL OF LONG-LOST CHARACTERS IN THE OFFSPRING OF CROSS- 

 BREEDS—MULTIPLE ORIGIN OF THE DOG INHERITED INSTINCTS VARIATION 



OF THE GOLD FISH AND SILKWORM MAN CAUSES PARTICULAR PARTS OF AN 



ANIMAL OR PLANT TO VARY WHILE OTHER PARTS CONTINUE UNALTERED 



MAIZE CABBAGE ARE THERE ANY LIMITS TO THE VARIABILITY OF A 



SPECIES? OBEDIENCE TO MAN UNDER DOMESTICATION OFTEN MERELY A 



NEW ADAPTATION OF A NATURAL INSTINCT — * FERAL ' VARIETIES DO NOT 



REVERT TO THE EXACT LIKENESS OF THE ORIGINAL WILD STOCK HOAV FAR 



DO DOMESTIC RACES DIFFER FROM AVILD SPECIES IN THEIR CAPACITY TO INTER- 

 BREED P—HYBRIDISATION OF ANIMALS AND PLANTS HERMAPHRODITE PLANTS 



NOT USUALLY SELF-FERTILISED WHETHER THE DISTINCTNESS OF SPECIES 



CAN BE TESTED BY HYBRIDITY TENDENCY OF DIFFERENT RACES OF DOMESTIC 



CATTLE AND SHEEP TO HERD APART— PALLAS ON DOMESTICITY ELIMINATING 

 STERILITY CORRELATION OF GROWTH. 



Domestic races, however divergent, breed freely 



TOGETHER.— We have seen that the indefinite modifiability of 

 species in the conrse of thousands of generations^ and under 

 gradually altered conditions in the organic and inorganic 

 world, is a question which has been seriously entertained 



by naturalists ever since the 



begfinning' 



of the present 



century. The changes brought about by the breeder and 

 horticulturist, and the new races to which they have given 

 origin, have always been appealed to in support of this theory 

 of unlimited variability. It may be said that man, in every 

 stage of his social progress, has been engaged in conducting, 

 with much patience and at enormous cost, a grand series of 

 experiments to ascertain how far it is possible to make the 

 descendants of common parents, both in the animal and 

 vegetable kingdoms, deviate from their original type. In pur- 



