"The differences between well-nourished and ill-nourished plants become little by little very noticeable. If individuals, whether animal or vegetable, are continually ill-fed and exposed to hardships for several generations, their organization becomes eventually modified, and the modification is transmitted until a race is formed which is quite distinct from those descendants of the common parent stock which have been placed in favourable circumstances.[277] In a dry spring the meagre and stunted herbage seeds early. When, on the other hand, the spring is warm but with occasional days of rain, there is an excellent hay-crop. If, however, any cause perpetuates unfavourable circumstances, plants will vary correspondingly, first in appearance and general conditions, and then in several particulars of their actual character, certain organs having received more development than others, these differences will in the course of time become hereditary.[278] "Nature changes a plant or animal's surroundings gradually--man sometimes does so suddenly. All botanists know that plants vary so greatly under domestication that in time they become hardly recognizable. They undergo so much change that botanists do not at all like describing domesticated varieties. Wheat itself is an example. Where can wheat be found as a wild plant, unless it have escaped from some neighbouring cultivation? Where are our cauliflowers, our lettuces, to be found wild, with the same characters as they possess in our kitchen gardens? "The same applies to our domesticated breeds of animals. What a variety of breeds has not man produced among fowls and pigeons, of which we can find no undomesticated examples!"[279] The foregoing remarks on the effects of domestication seem to have been inspired by those given p. 123 and pp. 168, 169 of this volume.[280] "Some, doubtless, have changed less than others, owing to their having undergone a less protracted domestication, and a less degree of change in climate; nevertheless, though our ducks and geese, for example, are of the same type as their wild progenitors, they have lost the power of long and sustained flight, and have become in other respects considerably modified.[281] "A bird, after having been kept five or six years in a cage, cannot on being liberated fly like its brethren which have been always free. Such a change in a single lifetime has not effected any transmissible modification of type; but captivity, continued during many successive generations, would undoubtedly do so. If to the effects of captivity there be added also those of changed climate, changed food, and changed actions for the purpose of laying hold of food, these, united together and become constant, would in the course of time develop an entirely new breed." This, again, is almost identical with the passage from Buffon,[282] p. 148 of this volume. See also pp. 169, 170.