154 THE TISSUES. 



In figure 1 1 3 is shown a neurone with relatively small cell-body 

 and short dendrites, from the granular layer of the human cere- 

 bellum. 



The function of the dendrites has given rise to considerable dis- 

 cussion. Golgi and his school regard them as the nutrient roots of 

 the cell, a theory which is opposed by Ramon y Cajal (93, 1 ), van 

 Gehuchten (93, I), and Retzius (92, II). According to the latter, 

 all the processes of the nerve-cell are analogous structures ; they 

 pass out from a sensitive element, and probably have a correspond- 

 ingly uniform function. 



In the spinal ganglia and the homologous cranial ganglia, are 

 grouped the cell-bodies of neurones (peripheral sensory neurones, 

 peripheral centripetal neurones) which differ in many respects from 

 those above described. In the peripheral sensory neurones the 



Neuraxis. 



Telodendrion. 



-- Nucleus. 



Fig. 113. Nerve-cell with dendrites Fig. 114. Ganglion cell with a pro- 

 ending in claw-like telodendria ; from the cess dividing at a (T-shaped process); from 

 granular layer of the human cerebellum ; a spinal ganglion of the frog ; X 2 3- 

 chrome-silver method ; X I Io - 



neuraxes and dendrites have essentially the same structure, both 

 forming part of a nerve-fiber. From a relatively large, nearly round, 

 oval, or pear-shaped cell-body there arises a single process, which, 

 at a variable distance from the cell-body, divides into two branches 

 forming a right or obtuse angle with the single process (T-shaped 

 or Y-shaped division of Ranvier, 78). Both of these branches form 

 the central axis of a nerve-fiber ; one of the branches passing as a 

 nerve-fiber to the spinal cord or brain, as the case may be ; the other 

 forming a nerve-fiber which passes to the periphery. (Figs. 114 and 

 115.) 



The ganglion cells of the spinal ganglia and homodynamic 

 structures of the brain are therefore apparently unipolar cells, but, 

 as Ranvier has shown, their processes are subject to a T-shaped or 

 Y-shaped division. The branches going to the periphery are re- 



