360 Prof. A. M. Mayer’s Experiments on the supposed 
tory nerve differentiated as highly as the covibrating apparatus, 
and in the case of the mosquito there is no known anatomical 
basis for such an opinion. In other words, my researches show 
external covibrating organs whose functions replace those of the 
tympanic membrane and chain of ossicles in receiving and trans- 
mitting vibrations ; while Helmholtz’s discoveries point to the 
existence of internal covibrating organs which have no analogy 
to those of the mosquito, because the functions of the former 
are not to receive and transmit vibrations to the sensory appa- 
ratus of the ear, but to give the sensation of pitch and to de- 
compose a composite sonorous sensation into its elements ; and 
this they can only do by their connexion with a nervous de- 
velopment whose parts are as numerous as those of the co- 
vibrating mechanism. Now, as such a nervous organization 
does not exist in insects, it follows that neither anatomical nor 
functional relations exist between the covibrating fibrils on the 
antenne and the ecovibrating rods in the organ of Corti, and 
therefore that neither Hensen’s observations on the Mysis (as- 
sumed by Helmholtz to confirm his hypothesis) nor mine on the 
mosquito can be adduced in support of Helmholtz’s hypothesis 
of audition *. 
The above-described experiments were made with care; and 
IT think that I am authorized to hold the opinion that I have 
established a physical connexion existing between the sounds 
emitted by the female and the covibrations of the antennal 
fibrilla of the male mosquito; but only a well-established phy- 
siological relation between these covibrating parts of the animal 
and the development of its nervous system will authorize us to 
state that these are really the auditory organs of the msect. At 
this stage of the investigation I began a search through the zoo- 
logical journals, and found nearly all that I could desire in a 
paper in vol. 11. (1855) of the ‘ Quarterly Journal of the Micro- 
scopical Society,’ entitled ‘Auditory Apparatus of the Culex 
mosquito,” by Christopher Johnston, M.D., Baltimore, U.S. 
In this excellent paper I found clear statements showing that 
its talented author had surmised the existence of some of the 
physical facts which my experiments and observations have 
established+. To show that anatomical facts conform to the 
* Also, the organ of Corti having disappeared in the lower vertebrates, 
it is not likely that it would reappear in the Articulata; and especially will 
this opinion have weight when we consider that the peculiar function of 
the organ of Corti is the appreciation of those composite sounds whose 
signification mammals are constantly called upon to interpret. 
+ A short time before the death of my friend Professor Agassiz, he wrote 
me these words :-—*‘ I can hardly express my delight at reading your letter. 
I feel you have hit upon one of the most fertile mines for the elucidation 
of a problem which to this day is a puzzle to naturalists, the seat of the 
organ of hearing in Articulates.”’ 
