104 J. GORDON "WILSON 



Tliis warm solution dissolves the fatty material which lies on the 

 surface of the membrane, loosens the epithelial scales, and in- 

 creases the action of the dye on the nerves. The effect may 

 be increased by brushing the external surface of the membrane 

 with a small clean camel's hair brush dipped in the fluid. Finally 

 the membrane is exposed to the air on a clean glass slide with 

 the side uppermost on which one wishes to get the better repre- 

 sentation of the nerves, usually the external. During this process 

 the tissue is kept moist with a solution of methlyene blue at a 

 temperature of 37° C. of the following strength : 



Methylene blue (nach Ehrlich) 0.5 per cent sol 10 cc. or 5 cc. 



Salt solution (0.75 per cent) 90 cc. or 95 cc. 



The time at which the nerves begin to appear varies with the 

 period after death at which the tissue is obtained, the sooner 

 after death the earlier they appear, but I have obtained results 

 six or eight hours after death when the body has been kept in a 

 cold chamber. If nerves do not appear within one hour it may be 

 regarded as useless to persevere. The dye is fixed in the nerve 

 by immersion of the tissue in an 8 per cent ammonium molybdate 

 solution. The subsequent treatment consisting of washing in 

 water, passing through alcohol and xylol, has been fully described 

 in a recent paper ClOb). The membrane may be mounted entire 

 in Canada balsam, or, the malleus being removed, it may be im- 

 mersed in paraffin and cut. Counterstaining when required, 

 appears to me to be best obtained by a weak alcoholic solution 

 of orange G. acid fuchsin. 



I find what may be called the principal nerve of the membrana 

 tympani, n. tympanicus major (n. t.m.), enters as a broad bundle 

 of fibers from the posterior edge of the membrana flaccida, on 

 the upper posterior segment of the membrana tensa (fig. 1).^ It 

 has an intimate relationship to the artery of the manubrium (a. 

 m.t.), the vessel at first lies posterior to the nerve but as the ves- 



' In a single methylene blue preparation not all the nerves take up the dye; in 

 one a particular group will appear well, while in a second it may be a different group. 

 This is particularly so in the human membrana tympani where the tissue is not 

 usually obtained till some hours after death. In the preparation from which this 

 drawing was made many of the nerves in the posterior superior and in the inferior 

 anterior quadrant did not stain. 



