MULLENIX: EIGHTH CRANIAL NERVE. 217 



related to the nerve fibres only by way of contact. There were still 

 those, however, who adhered to the older view, among whom were 

 Kaiser ('91), Niemak ('92), Ayers ('93), and Krause ('96). Ayers even 

 went so far as to maintain that the fibres of the eighth nerve originate 

 in the sense cells, as is the case with the fibres of the first nerve. 

 Held (:02) investigated the conditions in mammals, and came to the 

 conclusion that the sense cells are completely covered on their surface 

 with a richly nervous neuritoplasm, which takes its origin in an 

 intraepithelial branching of unmedullated fibres. The axoplasm is 

 represented by him as showing a netlike structure, and as intimately 

 grown together with the protoplasm of the sense cell. 



In 1904 Ramon y Cajal (:04^, :04'') published a method of silver 

 imj)regnation of nervous tissue which depended upon the reducing 

 action of hydrochinon or of pyrogallic acid. Later in the same year 

 (:04t') he published the results of the application of this method to 

 various nervous organs. His treatment of peripheral conditions was 

 meagre, but a small amount of space was devoted to an account of the 

 conditions found in the ear of chick embryos seventeen to nineteen 

 days old. His findings were in accord, in the main, with the contact 

 views of Retzius and others. He described two types of nerve fibres: 

 first, giant fibres, which make their way to the summit of the cristae 

 and expand at their ends to form a structure which is evidently identical 

 with the "Kelchbildung" previously described by Retzius. These 

 Ramon y Cajal regarded as separable from the sense cells with a good 

 degree of clearness; and, secondly, fine fibres, which pass chiefly to 

 the margin of the sensory area and end free between the peripheral 

 ends of the cells. 



Kolmer (:04) applied Ramon y Cajal's method to the investigation 

 of the conditions in the ear of the frog, and obtained results not incon- 

 sistent with the contact theory. He described the sense cells as en- 

 closed at their bases by an oval meshwork of fibrils, and, in some 

 cases, as being surrounded at their bases or near their tops by loops 

 of neurofibrillae. In a later paper Kolmer (:05a) stated that upon 

 further study, and by the close comparison of serial sections, he had 

 concluded that the loop-shaped structure previously described was a 

 part of a very complex pericellular network of neurofibrillae, which, 

 however, was rarely differentiated by the method employed. He also 

 maintained that neurofibrillae penetrate the sides of the sense cells 

 and form intracellular networks, which, likewise, are seldom impreg- 

 nated. He concluded that the fibrillae of the eighth and other sensory 

 nerves have no real terminations, but turn back to the fibrillae of the 



