LECTURES ON THE PHENOMENA OF FLIGHT 

 IN THE ANIMAL KINGDOM. 



By M. Marev, of tlie College of France. 



[^Translated from the Ecvue Des Cours Sdentiftques, for the SmWisonian Institution.'] 



We shall occupy ourselves on this occasion in the discussion of a 

 question which is connected with our first studies on motion, as one of 

 the functions of life, namely, with the — 



NATUEE OF FLIGHT IN THE ANIMAL KINGDOM. 



night is a process of locomotion, in some cases indispensable and in 

 others accessory to the life of an immense number of living beings. It 

 is not confined to insects and birds that live habitually in the air, or to 

 certain mammals, such as bats, but is also common to animals which 

 are essentially confined, by their organization, to a terrestrial or aquatic 

 life, such as flying and dragon fish, gecko-lizards, aud, above all, to ptero- 

 dactyles, a race at present extinct. The field on which we are about to 

 enter is very extensive ; and although it has been long cultivated, it 

 would not be surprising if we should find that it has not been entirely 

 exhausted, or that it is still capable of yielding new facts. 



In beginning, for the first time, the study of locomotion, we should 

 address ourselves to the origin of the phenomena connected with the 

 subject, and we would pause upon the elementary apparatus which is 

 its special organ, namely, muscular fiber, and also upon the elementary 

 function of this indispensable organ, namely, muscular contraction. We 

 have, however, considered these in their general application to motion 

 in i:>revious lectures, and need only recall them to mind in this place. 

 The evident manifestation of animal motion is the production of a 

 change of place, or locomotion; but what we are now to consider espe- 

 cially is aerial locomotion or flight. 



Animal motion presents a series of complex phenomena; for exam- 

 ple, when we bend a finger, and examine the series of events which 

 occurs in the production of the desired result, we find, at the beginning, 

 first, the operation of the will, ov ix, psychical action; secondly, the trans- 

 mission of the influence of the will, or a nervous action; thirdly, the 

 contraction of the muscles, or muscular action; and, fourthly, the motion 

 of the finger, which is a mechanical action. In the study of these phe- 

 nomena with which shall we commence"? A philosopher of the past, a 

 8piuozist, would not hesitate in answering, but would say at once, the 

 logical order should be observed; the examination of the action of the 

 will should be first made; and the other phenomena deduced from the 

 result of this, as the primary cause. But this method is the one which 

 the modern school of science rejects. The investigators of our day re- 

 verse this order, and, instead of descending from causes to effects, ascend 

 from eflects to causes, from more simple and evident phenomena to those 

 which are more complex and hidden. If we first attemj)t to grapple with 



