WORK OF THE PHYSIOLOGICAL STATION AT PARIS. 395 



by which nerves aiul muscles tire stimuhited, or to determine the char- 

 acteristics of the electricity generated by animals. The numerous 

 improvements introduced by M. d' Arson val iu the determination of tem- 

 peratures and the measurement of the calories generated by an ani- 

 mal according to its height, species, and the ])hysiological conditions 

 in wliich it is placed, should be here mentioned. 



All these apparatus also tend to become registers, and this makes 

 their indications comparable with each other and i)eimits us to assemble 

 in a single graphic table the curves of all sorts of phenomena. All 

 tend likewise to be applicable to man and to animals under normal con- 

 ditions without disturbing in any Avay the functions they are intended 

 to investigate. 



The zoologist, then, as well as the experimental physiologist, may 

 investigate in different species of ariimals the variation of function in 

 an organ corresponding to its A'ariation of form. It is here, as 1 have 

 before said, that union may be effected between the two sciences, long 

 separated from each other. 



II. 



Physiologists and naturalists ought to seek not only unity of method, 

 but also a favorable held for their joint investigations. The classical 

 physiological laboratory is not well adapted to anything but vivisec- 

 tions, while space, open air, and unobstructed light are indispensable 

 for the study of living creatnres. It often happens that it is difiticult 

 to secure all the conditions necessary; it is hardly possible to study 

 the physiology of insects except in the country; marine animals must 

 be studied at some maritime station with all the necessary instruments. 



It is, however, possible to set up near cities an experimental station 

 fulfilling thei)rinc!i)al conditions just noted. The Physiological Station 

 is the first establishment of this kind; it already afltords many resources 

 not elsewhere found; and is, besides, susceptible of important devel- 

 opments that may be made from time to time as the need for them is 

 felt. But in bringing this establishment to its present state many diffi- 

 culties were encountered which it nmy be useful to briefly consider. 



In 18GI, at the time when the graphic method of recording certain 

 physiological phenomena seemed sufficiently developed to permit an 

 analysis of the different kinds of movements, I attempted to use it for 

 determining the mechanism of locomotion in different species of ani- 

 mals. The movement of the wings of insects was quite easy to catch, 

 and besides, the theory of this kind of locomotion had been established 

 by a true synthesis, using artificial api)aratus, in which a motion of 

 translation was effected by agitating mechanical wings. This first suc- 

 cess made me think that the problem of the flight of birds, the details of 

 which almost completely elude direct observation, might be elucidated 

 by the same method, and that tame birds to which suitable apparatus 

 had been fitted would, when flying in an inclosed space, record the move- 



