762 THE POPULAR SCIENCE MONTHLY. 



easily be indicated by a bending of the sensory hairs of the eristcB 

 acousticcB as the liquid in the semicircular canals is thrown this 

 way or that by angular deviation of line of motion. Experi- 

 mental test of the theory is impossible, since, after injury of a 

 single semicircular canal, the birds refuse to fly at all. It must 

 rest, therefore, upon facts obtained from observation of habits 

 and methods employed by homing pigeons. If it is true, there 

 should appear some relation between the flight of a bird home 

 and the course by which it has been carried to the place of libera- 

 tion. It should either tend to retrace its course or to follow a 

 straight line home. However, the writer has not been able to 

 record a single fact which points in this direction. 



Graver objections must be admitted to obtain against the 

 theory of M. Caustier, tinted as it is by the " electro-magnetic " 

 romancing of the French hypnotists. He tells us of the bird, en- 

 dowed with " une nature eminemment eledrique," of " Velectricite 

 de I'air," of " magnetisme terrestre," of " Vaction physiologique du 

 magnet isme," and the like. This means that pigeons can sense cur- 

 rents of atmospheric electricity or terrestrial magnetism in such 

 a manner as to be guided by them ; and this can hardly stand 

 even as passing theory, while it remains so thoroughly proved 

 by the experiments of Hermann,* and these have been confirmed 

 with powerful dynamos in at least two laboratories in this coun- 

 try, that the magnetic field has not the least physiological influ- 

 ence (" nicht die geringste Wirhung ") upon the action of any 

 tissue or sense organ or upon the animal as a whole. 



But what say homing pigeons for themselves ? 



Of first importance to the study of a homing instinct is the 

 method which an animal employs to mark or locate its home. On 

 leaving a new camp for a day's hunt in the Bad Lands, a man 

 naturally turns about and makes a mental note of prominent 

 buttes in the vicinity. This butte with three pine trees on top is 

 just to the left of the gulch where the tents are pitched. " I can 

 tell it as far as I can see it," and he strikes out. Why may not 

 other animals adopt a similar method ? Concerning bees, Thomp- 

 son has observed that, " if the position of a hive be changed, the 

 bees for the first day take no distant flights till they have thor- 

 oughly scrutinized every object in its neighborhood." This 

 would seem to indicate a rational method of procedure. 



Upon their arrival in Madison, Wis., from Worcester, Mass., 

 the pigeons were kept confined in a large loft which had but one 

 window, and this happened to be upon the side next another barn 

 close by, so that it afforded no view of the surrounding country. 



* Hermann. Hat das magnetische Feld direkte physiologiscbe Wirkung ? Pfluger's 

 Archiv, vol. xliii, p. 217, 1888. 



