No. I.] THE VERTEBRATE EAR. 24 1 



bers of experiments, and hundreds of vertebrates, high and low, 

 have lost their lives on the altar of science (the protests of the 

 anti-vivisectionists notwithstanding), without the attainment of 

 the results hoped for, since the object of this sacrifice — the 

 determination of the function of the semicircular canals — had 

 become more and more difficult with the increase of physiologi- 

 cal experiments. 



This result was mainly due to the firm belief which had be- 

 come the basis of most attempts to solve the questions relat- 

 ing to the ear canals ; viz. that the canals must have some 

 function of a peculiar and special nature, which, owing to their 

 spatial relations, must be closely connected with the equilibra- 

 tion of the body. This view was supported by the fact that with 

 two exceptions all species of vertebrates had the same sort of 

 apparatus. The ear as a whole was treated as something unique 

 in the animal body, with no genetic relations to other structures, 

 and the canals, highly specialized portions of the ear organs. 

 It was perhaps impossible to make much progress so long as 

 this belief was allowed to dominate all conclusions from specu- 

 lation or experiment, but more might have been done had 

 physiologists earlier taken hold of the sadly neglected field — 

 comparative physiology. 



The first experimentalist to take up the subject of the func- 

 tion of the semicircular canals seems to have been Flourens, who 

 in 1828 found that Pigeons with resected semicircular canals 

 were unable to control the movements of their heads, and his 

 observations were later repeated by Cyon (62, 6'^^, 64), who de- 

 scribed the phenomena attending the division of the canals as 

 follows. After section of the external semicircular canal the 

 Pigeon moves its head from side to side around an axis passing 

 vertically through the head as the bird stands. 



After section of the posterior canal the movements are up 

 and down around a horizontal axis passing through both ears, 

 but after section of the anterior semicircular canal the move- 

 ments are diagonal components of the two just described. 

 These pendular movements cease after a time when the section 

 is one-sided, but they are more intense and persist longer when 

 they are bilateral. 



Flourens and Cyon maintained that the movements always 

 occurred around an axis at right angles to the plane of the sec- 



