582 The Sensory Organs. | September, 
Naturges. zii Halle, vii), described the olfactory cells of fishes, 
amphibians, birds and mammals, and strongly argued for their 
direct continuity with nerves. His theory rests on the complete 
chemical and morphological analogy between the central ends of 
the olfactory cells and the nerve fibrilla. Prof. Babuchin, 1868 
(Stricker’s Histology), says that he possesses a chloride of gold 
preparation from a tortoise, in which can be observed the imme- 
diate passage of the nerve fibrille into the epithelial layer, “ where 
they can be followed into the nuclei of the olfactory cells.” He 
says, “this might raise M. Schultze’s hypothesis to an actual fact 
if we possessed in the chloride of gold a substance which stained 
only nervous elements, and if this re-agent.were not so very 
uncertain in its action.” Von Brunn, 1875 (A. f. M. A. xii), 
describes, in addition to the epithelial and olfactory cells described 
by Clark and Schultze, a homogeneous membrane covering the 
olfactory region of mammals, and which is pierced by the per- 
ipheral processes of the olfactory cells. This arrangement would 
seem to exclude the epithelial cells from immediate contact with 
any substance inhaled into the nostril, and confine such contact 
entirely to the peripheral ends of the olfactory cells. This would 
go very far to establish the fact that the olfactory cell is the es- 
sential or percipient structure of the organ of smell. At any rate, 
it is a cell peculiar to the olfactory region, is constant throughout 
vertebrates, and like the corresponding structure in the organ of 
hearing, the weight of evidence is in favor of its direct nervous 
continuity. 
. 
The Organ of Taste—Here we meet with a peculiar dif- 
ficulty at the outset, and one to which the consideration of other 
organs is not subject. Itis at first a matter of doubt as to what 
structure really constitutes the organ of taste. From the litera- 
ture of the subject, however, I think it may be fairly attributed to 
the so-called taste-buds, as is almost unanimously done by the. 
investigators of these organs. The taste-buds are distributed 
most thickly where the sense of taste is most acute, and less 
thickly on parts of the tongue where the sense of taste, per se, is 
less but where the general sensibility is greatest, as the tip and 
i anterior part of the dorsum. What gives the most ground for _ 
_ doubt regarding their gustatory function, is that Verson has found _ 
them on the lower surface of the epiglottis and Krause on the 
ee of the same, The latter oT does not consider axes 
