458 EDWARD HORNE CRAIGIE 



There have also been recorded differences in the manner of 

 growth of certain sensory and motor cells, which seem to be of 

 such a nature as to demand a larger blood supply for the former. 

 These differences have been described by Donaldson and Na- 

 gasaka ('18), who observed that the spinal ganglion cells grow 

 with the growth of the body, each enlarging "nearly in propor- 

 tion to its entire fibers, but less rapidly than the corresponding 

 axes;" while in the case of the large spinal-cord cell bodies, "the 

 enlargement of the axon to meet the requirements of the increased 

 muscle mass to be innervated is ... . not accompanied 

 by any notable increase in the size or internal arrangements of 

 the cell." The growth of the spinal ganglion cell "is considered 

 as an adaptation for maintaining the sensory discrimination 

 despite the extension of the area supplied by a single neuron." 



Finally, one cannot altogether overlook the existence of what 

 are generally designated 'psychic' processes, whatever these may 

 really be, and whatever may be the nature of their relation to 

 physiological activity. Von Monakow ('16) believes "that the 

 material basis of the sentiments ought to be regarded as chem- 

 ical." Cannon and Crile both claim to have found evidence 

 of endocrine activity in emotions, and Achucarro believes that 

 the neuroglia may be involved in such processes. " 'Evidently, 

 then,' as Lagaro remarks, 'the nervous system and the endocrinic 

 glands act as one under certain circumstances and constitute 

 the basis of many changes in normal psychic life.' " (Or and 

 Rows, '18). Mott ('14) states quite decidedly that the physi- 

 ological basis of all mental activity, whether simple or complex, 

 is a group of biochemical processes involving oxidation and 

 hence absolutely dependent upon the blood supply. Thus it 

 is at least possible that the vascular differences recorded above 

 may be in part related to 'psychic' activities in which the respec- 

 tive centers are concerned. 



