CHAPTER XVII. 



OLD AGE. 



Changes in the entire body Change in the weight of the 

 encephalon In the lobes of the cerebrum In the thick- 

 ness of the cortex In the cerebellum Studies on paralysis 

 agitans Observations by Hodge on old age Influence of 

 specialisation Effect of exercise Order of dissolution 

 Decreasing productivity Multiple pathways Similarities 

 between fatigue and old age. 



IN advanced life the grosser changes in the body due 

 to growth are amply evident. By the condensation of 

 the skeleton and the greater curvature of the spine the 

 stature decreases towards the evening of life just as 

 towards the evening of each day the body has become 

 shorter. The bodily temperature falls from O'i-O'5C. 

 below that found in the prime of life. 1 The weight of 

 the active tissues decreases, that of the cell-multiplying 

 and blood-producing organs being most diminished, 2 

 but this decrease may be masked by the accumulation 

 of fat, though this also disappears in persons very old. 

 It has been suggested that even the shape of the skull 

 may alter at this time, but sufficient evidence for this 

 view is not forthcoming. In these total changes the 

 central nervous system bears its part. The tables (13 

 and 29) in Chapters IV. and VI. show that for sane and 

 insane persons of both sexes, the encephalic weight is 



1 Kelynack, Medical Chronicle, Manchester, 1892. 



2 Humphrey, Old Age, Cambridge, 1890. 



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