REPRODUCTION 585 



As old age comes on a general decline sets in, the rib cartilages 

 become calcified, and lime salts are laid down in the arterial walls, 

 which thus lose their elasticity; the refracting media of the eye 

 become more or less opaque; the physiological irritability of the 

 sense-organs in general diminishes; and fatty degeneration, di- 

 minishing their working power, occurs in many tissues. In the 

 brain we find signs of less plasticity; the youth in whom few lines 

 of least resistance have been firmly established is ready to accept 

 novelties and form new associations; but the longer he lives, the 

 more difficult does this become to him. A man past middle life 

 may do good, or even his best work, but almost invariably in 

 some line of thought which he has already accepted; it is ex- 

 tremely rare for an old man to take up a new study or change his 

 views, philosophical, scientific, or other. Hence, as we live, we all 

 tend to lag behind the rising generation. 



Death. After the prime of life the tissues dwindle (or at least 

 the most important ones) as they increased in childhood. 



Before any great diminution takes place, however, a breakdown 

 occurs somewhere, the enfeebled community of organs and tissues 

 forming the man is unable to meet the contingencies of life, and 

 death supervenes. "It is as natural to die as to be born," Bacon 

 wrote long since; but though we all know it, few realize the fact 

 until the summons comes. To the popular imagination the pros- 

 pect of dying is often associated with thoughts of extreme suf- 

 fering; personifying life, men picture a forcible and agonizing 

 rending of it, as an entity, from the bodily frame with which it is 

 associated. As a matter of fact, death is probably rarely asso- 

 ciated with any immediate suffering. The sensibilities are grad- 

 ually dulled as the end approaches; the nervous tissues, with the 

 rest, lose their functional capacity, and, before the heart ceases to 

 beat, the individual has commonly lost consciousness. 



The actual moment of death is hard to define: that of the Body 

 generally, of the mass as a, whole, may be taken to be the moment 

 when the heart makes its last beat; arterial pressure then falls 

 irretrievably, the capillary circulation ceases, and the tissues, no 

 longer nourished from the blood, gradually die, not all at one in- 

 stant, but one after another, according as their individual respira- 

 tory or other needs are great or little. 



While death is the natural end of life, it is not its aim we should 



