VOL. XXIV.] PHILOSOPHICAL TRANSACTIONS. 223 



most part he observes no membrane at all between them. The stapes stands on 

 the foramen ovale in a middle position, between vertical and horizontal ; it shuts 

 this hole exactly, being fastened to its margin by a thin membrane, but yet so 

 loosely, that it has the freedom of moving up and down; which motion he 

 thinks contributes much to hearing; for upon opening the ear of one that had 

 been very long deaf, he observed, that the ossification of this very membrane 

 was the only cause of his deafness. The fleshy belly of the musculus stapes, 

 first discovered in a horse by Casserius Placentinus, is contained in a bony 

 channel, excavated about the middle of the true Fallopian aqueduct laterally, 

 from which its tendon is obliquely carried to the head of the stirrup. 



Although those four little bones have no periosteum, yet several blood vessels 

 run upon them, and enter their substance, which is very compact and hard; 

 the stapes indeed is something brittle, not because it is more porous than the 

 rest, but because it consists only of one bony lamella. The fenestra rotunda 

 he sometimes observes to be of an oval figure: the membrane that shuts it is 

 fastened lower down than its margin. 



He describes several small holes that pierce the cranium, and open into the 

 tympanum just above the articulation of the malleus and incus; by these, ex- 

 travasated blood or purulent matter, contained within the skull, may be carried 

 into the cavity of the barrel ; from whence they may either pass through the 

 hiatus in the membrana tympani, or else by the tuba Eustachii, and so be eva- 

 cuated by the mouth. He proves the existence of such holes by injection, and 

 two practical observations. 



The duct that goes from the ear to the palate he calls, from its figure and 

 first observer, Bartholomaeus Eustachius, tuba Eustachiana: it consists of a bony, 

 cartilaginous, membranous, and fleshy part. The membrane that lines it is 

 full of glands. To dilate and keep this tube open, he has found out a new 

 muscle, which novus tubae musculus, as he calls it, rises fleshy from that por- 

 tion of the tube between the beginning of its cartilaginous part and its ex- 

 tremity; hence descending obliquely by the lower part of the internal ala of 

 the processus pterigoides, it becomes tendinous, which growing broader again, 

 is so inserted into the inferior margin of the membrane, that covers the 

 foramina narium ; where it joins with its fellow on the other side. 



The uvula, which he considers as part of the pharynx, is moved by three 

 pair of muscles, one known long ago, but ill described, and two new ones dis- 

 covered by himself. 1. Salpingo-staphylinus; which rises from the inferior 

 bony part of the Eustachian tube, whence it descends obliquely to its insertion 

 into the basis of the uvula, where it joins its fibres with its partner-muscle on 

 the other side. 2. Glosso-staphylinus; which comes from the lower part of the 



