THE PROTOPLASMA AND THE CELL. 



13 



dying in his eightieth year, has changed his nail two hundred 

 times, at least — and the nail appeared such an inanimate, ap- 

 parently unalterable thing ! 



We consider the nail cell a relatively long-lived constituent 

 of the body. We believe that most of the cells of our body 

 have a very much shorter existence. We repeat, however, 

 that it is a matter of belief, for no one can prove it, at pres- 

 ent ; but everything compels the view that, for example, the 

 red blood corpuscles, of whose multitude we spoke above, 

 have a much shorter existence than the elements of the 

 nails, and they are certainly resembled by many other cell- 

 varieties. 



Most cells being destined to an early death, how do they 

 die ? 



Science can give to this, at present, but an insufficient 

 answer. Certain cells, those of the outer surface of the body 

 and of many mucous membranes, dry up in their old age ; 

 the connection with the vicinity dissolves, the thing falls from 

 its bed. The red blood cells die by being dissolved in the 

 blood plasma. Others stick fast in the complicated tissue of 

 the spleen, and are likewise children of death ; for the blood 

 corpuscle lives only in the perpetual motion of the current ; 

 rest stamps it with the impress of death. 



Other cells show in their old age granules of lime salts. 

 They mummify. In this condition they may, as cell corpses, 

 possibly remain for a still longer time constituents of the 

 body. Generally, however, they soon afterwards become 

 dissolved. 



A very disseminated form of death of ani- 

 mal cells, in healthy as in unhealthy life, is 

 the so-called fat degeneration. In the place 



r . . ... Fig 17 — Fatty degen- 



01 the protoplasma, we perceive, in increas- crated cells from theGraa- 



• . fian follicles of the ovary. 



ing quantity, molecules of fatty matter 



(Fig. 17). They finally destroy the cell life and cell body. 



The human body daily loses, therefore, immense numbers 

 of its living corner-stones. How does it replace this loss ? 



We here enter a very interesting department of our science. 



