If, however, all this be true, how are we to account for the wonderful intellectual superiority of man? Haeckel gives an explanation which, although ingenious, is far from satisfactory. He says that it is owing to the fact that “man combines in himself several prominent peculiarities, which only occur separately among other animals.” The most important of these are the superior structure of the larynx, the degree of brain or soul development, and that of the extremities, the upright walk, and, lastly, speech. But, says Haeckel, “all these prerogatives belong singly to other animals—birds with highly-organised larynx and tongue, such as the parrot, &c., can learn to utter articulate sounds as perfectly as man himself. The soul’s activity exists among many of the higher animals, particularly with the dog, the elephant, and the horse, in a higher degree of cultivation than with man when most degraded. The hand, as a mechanical instrument, is as highly developed among the anthropoid apes as with the lowest men. Finally, man shares his upright walk with the penguin and other animals, while capacity for locomotion is more fully and more perfectly developed among many animals than with man.” Haeckel concludes, therefore, that it is “solely the fortunate combination of a higher organisation of several very important organs and functions which raises most men, but not all, above the animals.”[373] This explanation, however, appears rather to increase the difficulty than to remove it. Some of Haeckel’s statements might probably be challenged with success; but even admitting their truth, what cause can be given of the marvellous combination in man, of qualities possessed separately by animals, the highest in the class to which they belong?