56 THE EXTERNAL AND MIDDLE EAR, BY J. KESSEL. 



mucous membrane of the tympanic membrane of an old and deaf 

 woman, and were regarded by him as pathological formations. Their 

 importance as physiological structures was first recognized from my 

 own researches and those of Politzer (34 and 35). 



The mucous membrane of the tympanic cavity receives its 

 supply of nourishment from various quarters and from different 

 arteries. The principal artery pursues a very tortuous course 

 on the floor and over the promontory. The branches it gives 

 off often form circular and elliptical loops, and then break up 

 into a plexus of capillaries lying beneath the epithelium, 

 which transmits the blood traversing it into a subjacent 

 capillary plexus, the vessels of which rapidly increase in size, 

 and again discharge their contents into the comparatively 

 large veins of the periosteum. The arterial branches do not 

 always present these relations, since many run straight and 

 undivided till they suddenly break up into capillaries, which 

 often pass in considerable numbers between the fibres of the 

 foraminated membrane, in the same direction, and at equal 

 distances from one another, transmitting their contents into 

 large veins lying on the floor of the above-described system of 

 cavities. 



The lymphatics of the mucous membrane lining the tympanic 

 cavity exhibit the same relations as those of the membrana 

 tympani. They form in Man, in some parts, a system of tubes, 

 either presenting spherical dilatations, or large lateral diver- 

 ticula, which is chiefly situated in the periosteum, or which, 

 after presenting saccular expansions, opens out into the Jacunar 

 system. This tubular system is not however everywhere 

 present, but is in some parts, as upon the upper bony walls and 

 roof of the cavity, replaced by funnel-shaped or spherical and 

 intercommunicating spaces, which are again traversed by a fine 

 plexus ; appearances that are also presented in the tympanic 

 cavity of the Dog, as shall presently be more fully described. 

 I have frequently found these spaces clogged with white blood 

 corpuscles, which makes them resemble the follicles of a gland. 

 These appearances have probably led to the statement made 

 by Nasiloff, to the effect that he had discovered a lymphatic 

 gland in the mucous membrane of the tympanum, at the part 

 where it passes from the upper wall of the cavity to the 



