CAPACITIES OF JVERVE-CELLS. 2()5 



must be due to the nature of the attachment of the 

 fibres to the terminal apparatus. (Cf. chap. xiii. 3, 

 p. 217.) 



After we had carefully examined the peripheric ter- 

 minal apparatus of the motor nerves, that is to say, the 

 muscles, we were in a position to study the processes 

 in motor fibre. In order now to understand the action 

 of sensory fibres, it will be therefore necessary first 

 to obtain further knowledge of the central nervous 

 organs. 



The central organs of the nervous system, in ad- 

 dition to nerve-fibres, include, as we have seen (chap, 

 vii. 1, p. 105 et seq.\ also cellular structures, called 

 ganglion-cells, nerve-cells, or ganglion-balls. They 

 are not always globular, but are generally irregular in 

 form. Beside the forms represented in fig. 27 (p.' 106), 

 which occur scattered here and there in the course of 

 the peripheric nerves, forms such as those represented in 

 fig. 68 occur much more abundantly in the central or- 

 gans. They generally have many processes (four, six and 

 even up to twenty), which branch and unite together 

 like network. Many cells exhibit one process, differ- 

 ing from the others, which passes into a nerve-fibre 

 (nerve-process : cf. fig. 68, la and 3c). These nerve- 

 processes pass out from the central organ and form 

 the peripheric nerves. Within the central organ the 

 processes of the ganglion-cells form a very involved 

 network of fibres ; between these there are, however, 

 other fibres which completely resemble the peripheric 

 nerve-fibres. There is no reason for ascribing to these 

 fibres of the central organ qualities other than those of 

 the peripheric fibres. When in the central organ phe- 

 nomena are observed which never occur in the peri- 



