CHAP. XXVI.] VOLUNTARY MOVEMENTS. 561 



* Desires,' and further influenced in certain correlative tracts by 

 that mode or degree of activity which on its subjective side we 

 call ' Attention.' 



Deferred Primary Automatic Movements. 



Much difference exists among different Animals as to the degree 

 of perfection at the time of birth of these inherited cell-and-tibre 

 connections, and, therefore, similar differences exist among such 

 Animals, in regard to their power at birth of executing the several 

 Movements with which such Nervous Mechanisms are in relation. 



Thus, in some Birds at the time of their emergence from the 

 egg, and in some Quadrupeds at birth, much of the nervous 

 mechanisms concerned with Automatic Movements habitually per- 

 formed by such creatures, are so far perfected that these animals 

 are capable almost. at once of performing tho most complex Move- 

 ments without in any way requiring to 'learn' how to execute 

 them. The experiments of D. A. Spalding with Chickens and 

 young Pigs have revealed interesting facts in illustration of this 

 position (see pp. 188, 229). 



Many instances of an opposite character may, however, be cited 

 cases, that is, in which at the time of emergence from the 

 egg, or at the time of birth, other Birds or Mammals are in a much 

 less mature state of development, and in which their powers of 

 executing complex Movements of a similar order are notably less 

 advanced. 



The young of Canaries and many other birds, for instance, 

 remain for ten days or a fortnight unable to feed themselves or to 

 walk, and they may continue for nearly twice this time unable to 

 fly. But this backwardness in power of executing such Move- 

 ments, is obviously only one of the signs or accompaniments of 

 their generally backward condition of development. A bird can no 

 more fly without the aid of properly developed internal Nervous 

 Mechanisms than without wing-feathers, and the one set of struc- 

 tures are probably almost at* abortive as the other in youug 

 Canaries and in the young of other birds. 



The performance of many Movements that are ' primarily ' 

 Automatic in the Chick and birds like it, are, therefore, 

 deferred in Canaries and their allies till such times as the related 

 nervous and other mechanisms have had time to develop. Ground 

 is thus given for the supposition, commonly entertained, that such 



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