112 AVERS. [Vol. VI. 



cifying. In combination with chromic and bichromic solutions 

 it is very destructive of the fibres if left long in the solution. 



Kleinenberg's salt picric and all aqueous picric solutions 

 have little, if any, contracting effect on the hairs, and preserve 

 the band in its normal relation, but render it easily separable 

 from the ridge of Corti. 



Solutions of copper salts above i % in strength contract the 

 hairs too much, and cause rupture between the band and the 

 hair cells. In weaker solutions, and especially in combination 

 with I to 5 % of alcohol and of glycerine, the hairs are preserved 

 in the normal condition. 



Flemming's solution, if allowed to act on the entire embryo 

 for a short time only, seems to have a good preservative effect 

 on the hairs, and may be followed by alcohol and glycerine 

 with advantage. Alcohol alone, unless cautiously employed 

 during the first stage of the water-extracting process, causes 

 ruptures and contractions in the hairs. 



Chromic salts are useful if their action is not too violent or 

 continued too long, for they readily bring about distortions in 

 the hair band. 



Essential oils almost invariably cause much distortion even 

 of the carefully hardened hair band, and the paraffine bath usu- 

 ally adds something to the action of the clarifying medium. 



Ether and strong alcohol, when acting for a protracted period, 

 cause peculiar changes in the hair band, while 



Aqueous solutions of gum arabic leave the hair band, as well 

 as the organ of Corti, in very near their original form and re- 

 lations. 



The hairs of the organ of Corti while individually distinct, are 

 so close together as to necessitate their cohesion into a long, 

 relatively thin and narrow band. Its length in man is about 

 3.3 cm; in the cat, 2.3 cm.; in the rabbit, 1.5 cm. Its breadth 

 in man is 0.5 mm. ; in the ox, 0.48 mm. ; and in the rabbit, 0.39 

 mm. The band is slightly broader in the middle than at either 

 end, and somewhat broader at its upper than at its lower end. 



In thickness it varies in different parts of cross-section, which 

 tapers gradually from the origin of the component hairs from 

 their cells to the inner free border, which lies on or above the 

 limbus spiralis, where it fades away to a very thin edge. This 

 edge, though composed of the extremely fine tips of the inner 



