130 



PHYSIOLOGY OF CENTRAL NERVOUS SYSTEM. 



trine that the conduction of a nerve impulse through a neuron is 

 always in one direction, that the dendrites are receiving organs, so 

 to speak, receiving a stimulus or impulse from the axon of another 

 unit and conveying this impulse toward the cell body, while the 

 axon is a discharging process through which an impulse is sent out 

 from the cell to reach another neuron or a cell of some other tissue. 

 The nem'on, so far as conduction is concerned, shows a definite 



Fig. 59.- 



- Motor cell, anterior horn of gray matter of cord. From human fetus (Lenhos- 

 sek) : * marks the axon ; the other branches are dendrites. 



polarity, the conduction in the dendrites being cellulipetal, in the 

 axons, cellulifugal. 



The neuron doctrine, so far as the name at least is concerned, dates from 

 a general paper by Waldeyer, * in which the newer work up to that time was 

 summarized. The main facts upon which the conception rests were fiu-nished 

 by His (1886), to whom we owe the generally accepted belief that the nerve 

 fiber (axis cyUnder) is an outgro\\'th from the cell, and secondly by Golgi, 

 Cajal, and a host of other workers, who, by means of the new method of Golgi, 

 demonstrated the wealth of branches of the nerve cells, particularly of the 

 dendrites, and the mode of connection of one nerve unit with another. 



'Deut. med. Wochenschrift," 1891, p. 50. 



