NATURAL AND ARTIFICIAL PAGES 71 



difficulty, and only sketched by artists of exceptional 

 skill and patience. The movement of the wings of birds 

 in flight has been very successfully analysed by instan- 

 taneous photography. Some of the poses revealed must 

 familiarise the public with what can be, and, in fact, has 

 been, observed in the case of large sea-birds, by the 

 unassisted eye, and has been represented in pictures by the 

 more careful observers of nature among modern painters. 

 A large sea-bird sailing along with apparently motionless 

 wings has been photographed in the act of giving a single 

 stroke so rapid as to escape observation by the eye. 



An interesting question in regard to the movements of 

 the horse is that as to how far any known " pace " is 

 natural to that animal, and how far it has been acquired 

 by training and is, in a sense, artificial. We know so little 

 of the wild horse, and of the more abundant wild asses 

 and zebras, that it is difficult to say anything precise on 

 this question. There is only one region in which the true 

 original wild horse of the northern part of Asia and 

 Europe still exists. That is the Gobi Desert, in Central 

 Asia. This horse is known as Prevalsky's wild horse, in 

 honour of the Russian traveller who discovered it. Live 

 specimens are now to be seen in the Zoological Gardens 

 and elsewhere. It closely resembles the drawings of horses 

 made by the palaeolithic Cromagnard cave-men. A century 

 ago a wild horse, probably of the same race as this, inhabited 

 the Kirghiz Steppes, and was known as the Tarpan ; it is 

 now extinct. The more southern Arabian horse is not 

 known in the wild state, whilst the wild horses of America 

 are descendants of domesticated European horses which 

 have "run wild." I do not know of any studies of the move- 

 ments of the true wild horse, nor of those of wild asses and 

 zebras, carried out by the aid of instantaneous photography. 

 It would be interesting to know whether untaught wild 

 " equines " would fall naturally into the gaits known as " the 



