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slip like rings upwards over the basal ends of the bundles of 

 hairs borne by each hair cell, so that when the hair band finally 

 breaks loose from the top of the ridge, the film is firmly fixed 

 by its inner edge to the outer edge of the hair band, and be- 

 sides is usually closely applied to its surface, even if the action 

 of the reagent has not caused a soldering of the structures at 

 their points of contact. The fusion of the two structures does 

 not always happen as the removable nets indicate. 



The continuation of Loewenberg's net is the membrana reti- 

 cularis, which cannot get out of place or become distorted, owing 

 to the fact that it is perforated by holes, through which pass 

 the hair bundles, which under the circumstances act like so 

 many pegs to hold the membrana reticularis film in place, and, 

 in fact, do materially aid in stretching the film tight and straight. 

 On account of the coagulating and contracting action of such a 

 reagent as chromic acid, the membrane is shrunk, but the firm 

 fixation in the horizontal plane will not allow distortion of the 

 plane surface or a shrinkage of the whole area of the membrane, 

 so that the strain due to the shrinking action of the reagent 

 serves to render tense the connecting bars of the reticulum of 

 this so-called membrane. The remnant of the covering of the 

 ridge of Corti, which lies upon the inside slope, extending into 

 the bottom of the sulcus spiralis internus, is less frequently 

 detached as it is more protected. It may be seen attached to 

 the inner edge of the basal ends of the inner row of hair bundles 

 of the hair band occasionally, but on account of its position and 

 much smaller size, it is not so noticeable, and, so far as I can 

 learn from the literature, has hitherto escaped notice. 



I hope I have made it clear that there are in the living ear 

 no such structures with physiological roles as the membrana 

 tectoria, membrana reticularis, and Loewenberg's net, and 

 equally clear, I trust, that the structures of special value for 

 the physiologist in the organ of Corti or mammalian cochlear 

 organ are the hair-bearing cells, which stand on the crest of the 

 ridge of Corti, and whose bodies are connected with the brain 

 centres by the fibres of the cochlear nerve. 



In closing the chapter on tectorial membranes I will quote 

 the observations of Hasse (ii3, 1873), made in summing up 

 his knowledge of the vertebrate ear after a long investigation of 

 its structure. It will be evident that, although his observations 



