222 



THE GROWTH OF THE BRAIN. 



lower end of the lumbar enlargement. He then counted 

 all the fibres in these sections, making the table for 

 these localities, given below, and putting first the num- 

 ber of fibres in the cross-section of the cord for which 

 the hypothesis called, and then the number which was 

 actually enumerated, the results were found to be in 

 close agreement. 



TABLE 53. SHOWING THE NUMBER OF MEDULLATED FIBRES IN 

 THE CROSS-SECTIONS OF THE SPINAL CORD AT THE LEVELS 

 NAMED : FIRST, ACCORDING TO HYPOTHESIS ; SECOND, 

 ACCORDING TO ENUMERATION. THE LEVELS CAN BE 

 LOCATED IN FIG. 42. (Gaule.} 



A great many objections have been urged against 

 these figures, nevertheless there is here indicated an 

 orderliness in construction which was by no means 

 suspected, and which is of fundamental importance in 

 further studying the architecture of nerve centres. It has 

 been urged that the neurons divide in their course. A 

 few such observations have been made, but in the peri- 

 pheral nerves of man and the frog these divisions of 

 the neuron are exceptional. In the spinal cord of fish 

 such a division is seen in the case of the giant fibre of 

 Mauther, and the same also has been observed in the frog, 

 while recently Shcrrington has reported "geminal fibres" 

 in man. But at best the number of such geminal fibres is 

 small. When, however, the branches of the dorsal root 

 fibres after they enter the cord, or the branches given off 



