192 Macteay Memoriat Vouume. 
It is a matter of regret that we did not inject the living animal with a solution 
of methyl blue ;* but we were anxious to obtain specimens of all the organs, 
including the brain, hardened in suitable fluids; and we were not at the time aware 
that we should encounter any end-organs of particular interest. We have endeavoured 
ever since to obtain a second live specimen to subject to this process, but hitherto 
without success. 
For general histological investigation we used tissue treated with Flemming’s 
fluid, or Miiller’s fluid, and variously stained, the best results bemg obtained by 
hematoxylin or hematoxylin and eosin, and anilin blue-black. 
These peculiar organs are to be found in the skin covering both upper and lower 
jaws, and are not confined to the external surface only, but are freely distributed 
over the internal or buccal aspect, and are also found embedded in the mucous 
membrane covering the hard palate and that surrounding the horny molar teeth. 
The difference between the epithelium covering the buccal surface, and that on the 
external surface is very slight, and the transition from the one to the other very 
gradual, the thickness of the epidermis slowly diminishing as one passes inwards and 
backwards towards the palate. 
In the case of the upper “lip” the two surfaces are distinguishable owing to 
the much larger amount of pigment situated in the deeper layers of the epidermis 
covering the external surface. Such a distinction, however, does not obtain in the 
lower lip. 
Poultont+ has drawn attention to the presence of these same organs on the 
transverse slightly horny ridges, on the buccal surface of the lips at either side. 
We further find that, in sections of the horny molar teeth, there are columns 
perpendicular to the surface which in parts stain slightly with nuclear stains, and 
which, when seen under a high power, show a series of imbricated superimposed 
cells arranged in a manner such as we shall show to be characteristic of the rod-like 
organs met with in the neighbouring mucous membrane and in the general epidermis 
of the snout. This appearance in the horny teeth is so striking that we cannot but 
regard it as due to the presence in them of similar organs which have undergone 
more or less cornification in common with the surrounding epidermis, so as to form a 
structure of sufficient hardness to subserve the dental function. 
Our observations show that these organs having such an extensive distribution 
are most concentrated at the free margins of the upper and lower lips, especially the 
former. 
* Ehrlich, Abhand, k. Akad. Wiss. Berlin, Feb. 25, 1885. 
+ Loc. cit. 
