THE TRANSMUTATION OF SPECIES. 253 



subject, on the other hand, it might be supposed that 

 the giraffe did not in the first instance possess the extraor- 

 dinarily elongated neck by which it is now characterised; 

 but that it resembled the ordinary Ruminants, to which 

 it is otherwise allied, in having a cervical region of the 

 normal length. It might further be supposed that, to begin 

 with, the climate of Africa was moister than it now is, 

 and that the regions inhabited by the giraffe were not 

 liable, as they now are, to prolonged periodic droughts. 

 If we next assume that the climate of Africa underwent 

 gradually a change, in consequence of which it became 

 drier, and droughts became more frequent, it is clear 

 that the existence of the giraffe would be rendered difficult 

 or precarious, because its short neck would not allow 

 it to reach the higher shrubs, and the ordinary ground 

 herbage might be destroyed for many months together. 



According, however, to the conceptions of Lamarck, 

 the increasing frequency and severity of the droughts 

 would give rise to a gradual elongation of the neck of 

 the giraffe in successive generations, which would enable 

 the animal to dispense with the periodically destroyed 

 herbage, and to feed habitually on the foliage of trees 

 and shrubs. This gradual lengthening of the neck would 

 not, it need hardly be added, be produced in one 

 individual, but would be the result of the progressive 

 elongation of the cervical vertebrae in a long series of 

 generations. Hence, on Lamarck's view, the long neck 

 of the giraffe would have to be regarded as the direct 

 result of the surroundings of the animal, and not as a 

 pre-designed structure intended to meet foreseen con- 

 ditions. 



