vii THE STAGES OF LIFE AND DEATH 309 



cells (fatty degeneration, alterations in the coiling of the neuro- 

 fibrils, miliary necrosis, etc., as shown in Figs. 125, 126). 

 Although senile dementia is a disease sui generis, it is nevertheless 

 in closer affinity with simple physiological senility than with 

 the arteriosclerotic dementia which exists independently of 

 senility. 



From all these retrogressive changes in the different organs 

 and systems which we have described we may form an idea of 

 the functional modifications in the senile organism and can 

 readily understand its susceptibility to the many forms of disease 

 and discomfort which trouble old age. " Multa senem circumveniunt 

 incommoda," writes Horace, and few indeed are the old people who 

 are fortunate enough to attain to the average physiological length 

 of life, which should be about a hundred years. Cases of longevity 

 of nearly 150 years have indeed been known (Hermann), as well 

 as one case of 160, another of 163, another of 169, and two of 

 persons who lived to be nearly 180 (Burdach). 



VIII. The various forms of degeneration in the brain which 

 we have described may be fairly well deduced from the large 

 number of changes in the intelligence, the mental activity, the 

 emotions, the character, and in fact in the whole psychic personality 

 of the majority of men as they advance in years. The first and 

 commonest changes of a psychical order noted in old people are 

 those in their habits, together with modifications in their 

 character which make them diffident, credulous, susceptible, dis- 

 contented with everything, laudatores tempjris acti. Cicero said 

 that one of the advantages of old age was its exemption from the 

 passions, but this phenomenon if we consider it closely arises 

 from the fact that egotism, the desire for a quiet life, and a lack 

 of interest in the misfortunes or unhappiness of their neighbours 

 are predominant in the old. The old person is the survivor of 

 a vanished generation, and is lonely and forsaken in a new world 

 in which he is no longer strong enough to take any interest. As 

 a rule he does little but say how old he is, taking any one he 

 comes across into his confidence that he may be encouraged to 

 hope for long life. The psychic degeneration of the old is shown 

 by the gradual dissolution of the mental structure, the temporary 

 checks in the psychic current, the frequent failures of memory, 

 the weakening of the will and the imagination, and the uncertainty 

 in judgment. 



Whilst in the case of individuals whose tendencies are good 

 and who have led a regular life and escaped serious illnesses 

 these involutionary phenomena of the personality make their 

 appearance very late and are scarcely noticeable, in persons who 

 have inherited bad tendencies or have suffered from diseases 

 specially affecting the circulation these psychic changes are not 

 confined to the limits we have described, but are exaggerated, 



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