144 Journal of Comparative Neurology. 



suitable stimuli (forms of exercise, etc.) may be employed 

 to prolong the period of nerve making, and what activities 

 and what sorts of stimuli may unduly or precociously ex- 

 cite and exhaust such centres. 



There is some evidence that the brain continues to 

 increase in weight up to the thirtieth (females) or fortieth 

 year (males) yet there is as yet no adequate evidences as 

 to the nature or- conditions of the process. There is here 

 a most fascinating and promising field for the physiologist. 



These few suggestions may serve to illustrate the 

 purely physiological aspects of neurology. They will suf- 

 ficiently substantiate its claim to have a footing in practical 

 affairs. 



While we have noted the delicate balance of circula- 

 tory phenomena and nerve force and the control of the 

 fox-mer by the latter there is another aspect which appeals 

 to the psychologist. It is a familiar fact that when the 

 blood pressure of an organ is disturbed, as when a foot 

 becomes "asleep," curious and pronounced though vague- 

 ly localized smsations result. It is no less true that the 

 changes in blood pressure due to psychical reflexes have 

 such accompaniments. The "sinking at the heart," ting- 

 ling at the extremities, peculiar twinge in the axils, and the 

 indescribable "gone" sensation in the abdomen due to the 

 shock of a sudden report, or a concept of a certain event, or 

 the sight or odor of blood are instances of sensation no less 

 powerful because vaguely localized. Just because they are 

 unlocalized they associate themselves with our empirical 

 ego and become the sensationial element in emotions. It 

 is hardly too much to say that every emotion has some 

 sensational element bound up with it. Elimination of the 

 latter, when possible, leaves us a residuum somewhat dif- 

 ferent from the emotion. In the study of these organic 

 sensations we doubtless have hope of a clue to the elimina- 

 tion of one of the least satisfactory sections of modern psy- 



