THE EXTERNAL EAR. 37 



layers), the former proceeding from it, the latter lying behind 

 it, yet in such a manner that the uppermost part of the an- 

 nulus of circular fibres runs outwards from the malleus, and 

 passes along its outer side. Gruber (8) subjected the mode of 

 attachment of the malleus to the membrana tympani to fresh 

 examination, and described a till then unknown cartilaginous 

 structure which commences above the short process, and ex- 

 tends for half a millimeter below the handle. The cartilage is 

 firmly attached to the lower two-thirds of the manubrium; but 

 above, where the processus brevis is present, it is not attached } 

 but forms a kind of joint, the cavity of which is filled with a 

 synovian-like fluid. Still more recent examinations of this 

 part made by Prussak (36), myself (17), and Moos (29), agree in 

 showing that a third part of the processus brevis consists of 

 cartilage, which, however, passes uninterruptedly into the 

 osseous portion. According to Prussak and Moos, a thin layer 

 of cartilage cells is also to be found beneath the entire peri- 

 phery of the periosteum of the manubrium, not only in the 

 new-born child, but in adults and old persons. 



I have very recently repeatedly studied this part in 

 tympanic membranes that were still in connection with the 

 malleus, and taken from persons of different ages. In embryoes, 

 from the third to the ninth month, the ossicula are still in the 

 condition of cartilage, and have the advantage of being fit 

 for section without preparation, whilst those of newly born 

 children and of adults require to be first subjected, to some 

 decalcifying process. If sections be so made as to exhibit the 

 membrar.a tympani and the malleus in their natural connec- 

 tion, the malleus appears (with especial distinctness in em- 

 bryoes) to be invested by a periosteum quite independently of 

 the membrana propria, and to be only in connection with the 

 latter by a duplicature of the mucous membrane, having a 

 breadth of 0*2 to OS of a millimeter. At the point where the 

 processus brevis is subsequently developed, a cluster of highly 

 retractile nucleated cells occurs, lying above the periosteum, 

 and in the substance of the duplicature. These elements, 

 persisting throughout life as cartilage cells, form a mass inti- 

 mately connected with the bony part of the processus brevis, 

 which develops towards the end of foetal life with coincident 



