THE SENSE OF TASTE. 133 



serves as a protective covering to the cutis. The accompanying figures, repre- 

 senting a section of three sorts of papillse magnified, may serve as the grouncl- 



1 1 1'. 





'/^:,\^mB 



III 



work of a more exact description of each. In figure I is presented the section of a 

 filiform ; in figure II that of a fungiform ; and in figure III that of a circumvallate. 

 In all of them the part designated by a represents the epithelium, consisting of 

 squamous and cellular layers; that marked h the underlying mucous membrane. 

 It will be seen at first sight that the epithelium in neither form invests the sub- 

 jacent mucous membrane as a glove does the finger, so that the outer surface 

 of the former shall present an exact impression of that of the latter. In the 

 filiform papillae it will be observed that the epithelium has a number of long 

 antenna-like excrescences, giving the papillfc the appearance of a brush, while in 

 the others this covering is externally smooth, notwithstanding the inequalities 

 of the underlying membrane h, whose surface exhibits in each example a num- 

 ber of successive and rather narrow eminences of a sugar-loaf or conical form. 

 What purpose the antennte of the first form subserve it is impossible to con- 

 jecture; but, as regards the regular elevation of the proper mucous membrane, 

 their presence alike in each of the three kinds of papillte, as well as the circum- 

 stance of their existence likewise in the outer skin, leads to the conclusion that 

 wherever they occur, whatever otherwise their diversity, the physiological 

 signification which they bear must be the same. Now, as the microscope shows 

 us, that, as regards the outer skin and in part, at least, the mucous membrane of 

 the tongue, the finest branches of the blood vessels and the terminal extremities 

 of the nerves are found in these little eminences, the inference is obvious that 

 this peculiar formation of the surface is imposed on account of the organic eon- 

 tents of the eminences, providing, as it does, suitable receptacles in the periphery 

 for the ends of the vessels, and especially the nerves, and securing their regular 

 distribution over the surface. We may conceive that it behooved that the 

 ends of vessels and nerves should closely approach the outer surface at a regu- 

 lated distance from one another, which purpose indeed might have been attained 

 had these minute organs penetrated at certain intervals from the mucous mei% 

 brane into the loose strata of the epithelium ; but then they must have wanted 

 a sutficieutly stable involucrum to protect them against the pressure and con- 

 tinual wasting of the shifting elements of that covering. Now, such protection 



