584 The Sensory Organs. | September, 
tissue to the bundle of nerve-fibres in the body of the papilla.” 
In 1869 (Quart. Journal Micr. Science), Beale reiterated the same 
statement. In 1867, Engelman (A. f. M. A., iv) investigated 
the taste epithelium of the frog, and in the essential points of a 
cell with peripheral and central processes, and of the last being 
continuous with nerve-fibre, he agrees with Axel Key. Dr. Mad- 
dock, 1869 (Monthly Microscop. Journal), also investigated the 
same structure. He describes the taste-cells or rod-cells, as he 
calls them, and strongly supports the view of their direct nervous 
continuity. He says that the sensory nerves of taste do not ter- 
minate in free ends, “ but in terminal organs consisting of nerve 
matter surrounding a germinal mass or nucleus; in fact,” says he, 
“ I regard them to the plexus of nerves beneath the papilla in the 
same relation as the retinal rods to the optic nerve.” 
In 1863 (Z. f- W. Z., Bd. xii), F. E. Schulze redescribed the 
taste disks of fishes and laid great stress on the fact that these 
structures are found in greatest number just where the glosso- 
pharyngeal nerve is most thickly distributed. They are found on 
the gums, the tongue rudiment, the inner side of the gill arches 
and the barbels, but also in lesser numbers on the lips and skin 
of the head and body. These last, as Schulze supposes, are 
probably for the purpose of perceiving at some distance sub- 
stances dissolved in the water. He describes the taste-disk as _ 
consisting essentially of two kinds of cells, one being merely a 
supporting structure, and the other the percipient structure. The 
latter bears a central and peripheral process. In 1867, the same 
observer (A. f. M. A. iii, p. 152), states that the peripheral pro- 
cess bears a small hair as it does in mammals. In 1870(A. f. M. 
A.), he also described the taste-discs of the tadpole, and remarked 
their close resemblance to those of fishes, which might almost 
have been predicted. 
In 1868, Schwalbe (A. f. M. A. iv,) and Loven (Ibid.) de- 
scribed almost simultaneouslye and independently the taste- 
buds of mammals. Their descriptions agreed in all essential 
points; namely, in there being two kinds of cells, one having the 
value of a protective or supporting structure, and another which 
_ had a central and peripheral process and which was probably 
- continuous with nerve-fibre, which in its chemical reaction it re- 
sembles (Engleman in Strickers’ Hdb.). Subsequent investigators 
have merely corroborated the results of the preceding. Thus, von 4 
