172 Journal of Comparative Neurology 



word nucleus referring either to the cluster of cells from which 

 a nerve originates, or to the small area of caryoplasm situated 

 at or near the center of one of these same cells. 



The word nidus as used by Spitzka or nidulus by Herrick 

 would be equally appropriate to this group of cells and would 

 render much easier the path of the beginning neurologist. 



The present confusion is being largely augmented by the 

 various applications of the word neuron. The term is derived 

 from the Greek and means a nerve. It has been used for some 

 time in entomology for a nervure or a vein of an insect's wing. 

 Lowne (1883) applied it to a portion of the eye of some inver- 

 tebrates. Wilder (1884) proposed its application to the whole 

 cerebro-spinal axis. It correlates very well with the names of 

 the other two longitudinal body axes, axon and enteron. He 

 has also adopted neuraxis from Robin (1877) m this same sense. 

 Waldeyer (1891, Deutsch. Med. Wochenschrift) includes under 

 neuron a single nerve cell with its appendages as a nerve unit. 

 Kolliker, (1893, Handbuch der Gewebelehre des Menschen, pp. 

 107, 108) applies the term neuron to certain fiber tracts or 

 columns of the myel, differentiating them according to their 

 functions. Schafer (1893) restricts its use to the axis-cylinder 

 process alone. The latter writer has proposed a new classifica- 

 cation of nerve cells in the light of recent investigations and 

 bases it upon the number and kinds of processes attached to the 

 cells. For the protoplasmic processes he employs the term 

 dendrons, analogous to the German form dendtiten ( His). 

 Nerve cells may be divided into dcndric or adendric ; the 

 cells of the spinal ganglia are given as examples of the latter, 

 but every nerve cell has an axis-cylinder process and is either 

 mononeuric or polyneutic (dineuric, trineuric, etc.). Kolliker 

 (1893) rejects neuron as standing for a nerve unit because in its 

 original Greek meaning it stands simply for a nerve ; according 

 to this standard its use as a synonym for the cerebro-spinal axis 

 with its entocinerea and its central canal would be inappropriate 

 as would likewise its application to the axis-cylinder process. 

 The same writer proposes neurodendren or neurodendriten as 



