"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.
"Where can our many domestic breeds of dogs be found in a wild state? Where are our bulldogs, greyhounds, spaniels, and lapdogs, breeds presenting differences which, in wild animals, would be certainly called specific? These are all descended from an animal nearly allied to the wolf, if not from the wolf itself. Such an animal was domesticated by early man, taken at successive intervals into widely different climates, trained to different habits, carried by man in his migrations as a precious capital into the most distant countries, and crossed from time to time with other breeds which had been developed in similar ways. Hence our present multiform breeds."[283]
Here, also, it is impossible to forget Buffon's passages on the dog, given pp. 121, 122. See also p. 223.
"Observe the gradations which are found between the ranunculus aquatilis and the ranunculus hederaceus: the latter—a land plant—resembles those parts of the former which grow above the surface of the water, but not those that grow beneath it.[284]
"The modifications of animals arise more slowly than those of plants; they are therefore less easily watched, and less easily assignable to their true causes, but they arise none the less surely. As regards these causes, the most potent is diversity of the surroundings in which they exist, but there are also many others.[285]
"The climate of the same place changes, and the place itself changes with changed climate and exposure, but so slowly that we imagine all lands to be stable in their conditions. This, however, is not true; climatic and other changes induce corresponding changes in environment and habit, and these modify the structure of the living forms which are subjected to them. Indeed, we see intermediate forms and species corresponding to intermediate conditions.
"To the above causes must be ascribed the infinite variety of existing forms, independently of any tendency towards progressive development."[286]
The reader has now before him a fair sample of "the well-known doctrine of inherited habit as advanced by Lamarck."[287] In what way, let me ask in passing, does "the case of neuter insects" prove "demonstrative" against it, unless it is held equally demonstrative against Mr. Darwin's own position? Lamarck continues:—