OF EXCREMENTIT10US MA TTERS. 



203 



animals just as we can see the movements of the 

 blood, lymph, and chyle corpuscles, and the wonder- 

 ful alterations in form and size of the mucus and pus 

 corpuscles and portions detached from them. 



Many circumstances, however, render it far more 

 probable that the act of secretion, and " elimination " 

 of excrementitious substances from the blood, does not 

 involve the destruction of the cell. That every cell 

 grows old and dies is certain ; but the process is 

 much slower than it would be if the functional 

 activity of the cell involved its death as a whole. 

 The facts arrived at from a careful study of the cells 

 at different stages of development lead me to con- 

 clude that every cell, instead of secreting only its own 

 weight of matter, elaborates and eliminates a hun- 

 dred, or a thousand, or ten thousand times its weight 

 of material in its lifetime. The doctrine generally 

 entertained upon this point involves an extravagance 

 of cell destruction which neither the results of ana- 

 tomical observation nor the conclusions arrived at 

 from physiological experiments permit us to enter- 

 tain. 



In secretion and elimination it is probable that the 

 germinal matter of the cell absorbs the materials from 

 the blood, and converts these into matter like itself, 

 while at the same time a portion of the germinal matter 

 already existing dies, and undergoes conversion into 

 those substances which constitute the secretion, ac- 

 cording to the explanations given in my papers on 



