AN ESSAY ON LONGEVITY. 



the organs are delicate. . . . Thus, a certain solidity 

 of general organisation and a suitable condition of 

 the vital organs are the second condition on which 

 length of life depends. 3rd. The consumption (of 

 vital force and of organs) may be more or less rapid, 

 consequently its duration, or, what amounts to the 

 same thing, that of life, may be, other things being 

 equal as regards forces and organs, shorter or longer, 

 according as the act of destruction operates with more 

 or less intensity. 4th. Finally, since the reparation 

 of losses is the principal means of counteracting con- 

 sumption, a body which has the most perfect means 

 of regeneration, both internal and external, will en- 

 dure a longer time than one not provided with these 

 means. In a word, the duration of life in a being 

 depends on the sum of the vital forces which it 

 possesses, on the greater or less consistence of ' its 

 organs, on the rapidity or the slowness of its con- 

 sumption, and on the perfection or imperfection of 

 regeneration.' '• 



The only criticisms on these views which it is at 

 present useful to make, is that they involve certain 

 ideas which have become modified with the advance 

 of science, and hence require to be adapted to present 

 knowledge. In the sequel it will be seen how far 

 they differ or agree with modern conclusions. 



' Hufeland observes in one passage, ' The more imperfect the or- 

 ganisation the longer the life,' after describing the prolongation of life 

 in plants by pruning. His own facts are sufficient to refute this as a, 

 general law. The truth is the very opposite of this. 



