1879.] Ox the Morphology of the Semicircular Canals. 373 
thing to prevent the waves from meeting in exactly the same 
phases. If so, the effect of the semicircular canals would be to 
‘increase the intensity of sounds. 
Various other uses have, at times, been assigned to the semi- 
circular canals, such as the estimation of the direction of sound, 
or even the appreciation of pitch, besides which, conclusions have 
been drawn based on vivisection. Theories concerning pitch were 
held prior to the understanding of the structure of the cochlea, 
and may be dismnissed without discussion. Those concerning the 
direction of sound are not borne out by fact. In the first place, 
as the contradictory results of investigators show, the power 
among animals of distinguishing the direction of sound is not 
well marked, and even if it were it would be no proof that this 
pewer lies in the semicircular canals. Again, it is self-evident 
that the direction of sound cannot be maintained while passing 
through the auditory meatus and tympanum, and if we are told 
that the semicircular canals appreciate vibrations transmitted by 
the skull, the conditions are singularly unfavorable, for just in 
_ those animals in which an appreciation of the direction of sound 
would seem the most important, @. ¢., birds and mammals, the head 
is generally covered by a non-conducting material, feathers or hair. 
The power of distinguishing the direction of sound seems to 
me rather to be connected with the degree of development of the 
auricle and the degree of its movability, or the power the animal 
has of quickly adapting the head to various positions, so that it 
can determine that position in which the impression is received 
the most strongly, and thence infer the direction of the sound. 
The theories based on the vivisection of the semicircular canals, 
involve a method of reasoning that to me is not logical. To say 
that the results of a terrible mutilation of one of the most highly 
specialized parts of the body, namely, the head, are due to the 
destruction of any one organ or part contained in it, is certainly 
reasoning from incorrect premises—is certainly leaving out a 
large class of the facts. Secondly, to predicate that the function 
of an organ is the inverse of certain phenomena obtaining by its 
mutilation, is less logical still. To my mind the experiments of 
Flourens, Goltz and others, do not demonstrate that the results 
were due only to the mutilation of the semicircular canals, or 
that even if this were the case, anything could be predicated con- 
cerning their function. To use an apt illustration, let us take a 
watch and let us imagine that it was to us a new and strange 
