III. 



THE LAWS OF VARIABILITY WITH EESPECT 

 TO ANIMALS AKD PLANTS, 



The Varia- I SHALL in this Tolume treat, as fully as my 



mala and ' materials permit, the whole subject of varia- 

 Plants under tion under domestication. We may thus hope 

 tio^%ol.*'i *° obtain some light, little though it be, on the 

 page 3. causes of variability, on the laws which govern 



it — such as the direct action of climate and food, the 

 effects of use and disuse, and of correlation of growth — 

 and on the amount of change to which domesticated or- 

 ganisms are liable. 



Although man does not cause variability and can not 

 even prevent it, he can select, preserve, and accumulate 

 the variations given to him by the hand of Nature almost 

 in any way which he chooses ; and thus he can certainly 

 produce a great result. Selection may be followed either 

 methodically and intentionally, or unconsciously and unin- 

 tentionally. Man may select and preserve each successive 

 variation, with the distinct intention of improving and 

 altering a breed, in accordance with a preconceived idea ; 

 and by thus adding up variations, often so slight as to 

 be imperceptible by an uneducated eye, he has effected 

 wonderful changes and improvements. It can, also, be 

 clearly shown that man, without any intention or thought 



