10 THE GUSTATORY ORGANS, BY TH. W. ENGELMANN. 



of the mucous membrane to which they are firmly adherent, 

 or they gradually diminish in size, and suddenly break up into 

 several processes that often undergo subdivision, but in many 

 instances do not reach the surface of the membrane. 



In preparations obtained from the Sheep, and treated with perosmic 

 acid, Schwalbe found a circlet of fine short hairs at the apex of the 

 bulb, the points of which converged towards the interior of that 

 structure, and he was then led to the conclusion that they sprang from 

 the apices of the investing cells. These small hairs did not undergo 

 solution in caustic potash lye, even after long maceration, but were no 

 longer distinctly visible after isolation of the bulbs in solutions of chromic 

 acid. Their presence could not be distinctly demonstrated either in 

 other animals or in Man. Investing cells, whose inferior extremities 

 were prolonged into slender processes, were easily obtained by Loven 

 and Schwalbe from the gustatory bulbs of Man and of the Calf. The 

 processes were never varicose, but often presented a capitate enlarge- 

 ment at their extremity. Some of the investing cells depicted by 

 Loven * call to mind the forked cells of the Frog, hereafter to be 

 described ; and, like these, are possibly peculiar forms of true 

 gustatory cells. The long axis of the investing cells is usually 

 parallel to that of the bulb, and varies within the same limits as 

 these in Rabbits, for example, between ^-045 and 0-065 of a 

 millimeter. The investing cells of the same bulb are not all of equal 

 size ; but those of the outermost layer are usually the largest and 

 widest, and at the same time the flattest. Those of the inner layer 

 are shorter and more cylindrical. 



The gustatory cells (fig. 276, a and 6) are long and thin 

 organs, that are always homogeneous and highly refractile. 

 Each consists of an elliptical body prolonged at its upper pole 

 into a moderately broad, arid at its inferior pole into a slender, 

 process. The body is formed by a vesicular nucleus surrounded 

 by a very thin layer of homogeneous substance or "protoplasm." 

 The superior broader (peripheries) process is in the Rabbit quite 

 cylindrical, somewhat attenuated towards the apex, in general 

 about two and a half to three times longer, and at its middle 

 about half as broad, as the nucleus of the cell. The apex is 

 usually obliquely truncated and prolonged into a short hair or 

 cilium (fig. 276, a). 



* Loc. cit., infra, fig. 6, e, g, and h, i, j. 



