68 CONTRIBUTIONS TO ZOOLOGICAL PATHOLOGY. 
ation, especially the syphilitic form, of the tonsils and mucous 
membrane of the pharynx. In these latter cases it is dependent 
on the existence of a previous disease, and is, therefore, merely a 
concomitant or secondary affection, while in the case under con- 
sideration, it existed alone, as the primary form of disease. The 
structure and arrangement of the folds of the dermo-mucous mem- 
brane seen at the anterior chink of the larynx, differs a little in 
the horse from that which we find in the feline tribe of animals. 
In the horse, the investing membrane of the tongue at its base, 
after covering the free portion of the epiglottic fibro-cartilage, ex- 
pands on either side, in the form of a large depression, to become 
the covering of the side of the pharynx, while in the mesial plane, 
and from either edge of the base of the epiglottis, a large and com- 
paratively loose fold extends backwards and upwards to the apex 
of each arytenoid cartilage, forming, as in man, the aryteno-epi- 
glottidean folds. Between the edges of these folds the anterior 
aperture of the larynx is situated. In the depressions on either 
side of the folds there are an immense number of mucous follicles 
opening on the free surface, and evidently serving the purpose of 
tonsils; and even in the rounded external edge of the aryteno- 
epiglottidean folds several large crypts are seen, especially towards 
the base of the tongue. Between these duplications of the mucous 
membrane a very considerable quantity of loose, reticulated, and 
very vascular cellular tissue is situated ; and when a comparison 
is made with the other parts forming and bounding the rima glot- 
tidis, it will at once be seen, that here the sub- mucous tissue is 
more loose than in any of them, and consequently that it is the point 
in which the immediate effects of increased vascular action will be 
most speedily produced. 
In the feline tribe, these folds that stretch from the sides of the 
epiglottis upwards and backwards do not proceed exactly to the 
apices of the arytenoid cartilages, but, before reaching them, pass 
downward along the external sides of the cricoid cartilage, and 
around the bases of the arytenoids, where they again become united 
in the mesial plane, above the latter cartilages. They are much 
more prominent and distinct in this class of animals than in the 
solidungulae ; their cellular tissue is more abundant superiorly and 
posteriorly; and what is of importance, within the laryngeal sur- 
faces of their free edges several small granular masses are situated, 
composed of pyriform mucous follicles, whose apertures all open 
towards the larynx. Around these glands there are an abun- 
dance of bloodvessels, which, when injected artificially, form a 
complete scarlet surface. From the prominence of the folds in 
these animals; from the looseness of their contained cellular tissue, 
and the abundance of their bloodvessels, it may therefore be 
