240 



NORMAL HISTOLOGY. 



which arise chiefly in the column of Goll, pass through the sub- 

 stance of Rolando, and then form an expanding bundle distributed 

 in the anterior horn of the gray matter, where they are in associa- 

 tion with the dendrites of the motor cells in that region (these 

 fibres form the reflex bundle of Kolliker, Fig. 222, H) ; fourth, 

 collaterals springing from fibres in the posterior column, passing 



Cross-section of the spinal cord of a newborn child, showingthe distribution within the gray 

 matter of the collaterals from the neurites of the white matter. (R. y Cajal.) a, anterior 

 fissure ; B, pericellular branches of the collaterals from the anterior column ; C, collaterals 

 of the anterior commissure; D, posterior bundle of collaterals in the posterior commis- 

 sure ; E, middle bundle of the posterior commissure ; /, anterior bundle ; G, collaterals 

 from the posterior column ; H, senso-motory collaterals from the posterior column ; 

 I, pericellular terminations of collaterals in the posterior horn ; J, collateral terminations 

 in the column of Clarke. 



through the posterior commissure of gray matter and ending in the 

 substance of Rolando of the opposite side (Fig. 222, D). 



The reflex collaterals arising in the posterior column are shown 

 in Fig. 223, where their teleneurites are in close relations with the 

 teledendrites of the motor cells e. 



The centripetal or sensory neurites of the posterior spinal nerve- 

 roots spring from the ganglion-cells of the spinal ganglia. When 

 they have entered the white matter of the spinal cord they divide 



