DECLINE OF THE SYSTEM. 623 



with regard to this last stage of life, its pheno- 

 mena- must be observed in cases where the sys- 

 tem has been wholly entrusted to the operation 

 of her laws. When death is the simple conse- 

 quence of age, we find that the extinction of the 

 powers of life observes an order the reverse of 

 that which was followed in their evolution. The 

 sensorial functions, which were the last perfected, 

 are the first which decay ; and their decline is 

 found to commence with those mental faculties 

 more immediately dependent on the physical 

 conditions of the sensorium, and more especially 

 with the memory, which is often much impaired, 

 while the judgment remains in full vigour. The 

 next faculties which usually suffer from the 

 effects of age are the external senses, and the 

 failure of sight and of hearing still farther con- 

 tributes to the decline of the intellectual powers, 

 by withdrawing the occasions for their exercise. 

 The actual demolition of the fabric commences 

 whenever there is a considerable failure in the 

 functions of assimilation : but the more imme- 

 diate cause of the rapid extinction of life is 

 usually the impediment which the loss of the 

 sensorial power, necessary for maintaining the 

 movements of the chest, creates to respiration. 

 The heart, whose pulsations gave the first indi- 

 cations of life in the embryo, generally retains 

 its vitality longer than any other organ ; but its 

 powers being dependent on the constant oxida- 



