THE COMMON FACULTIES 263 



This is the place to show that nutrition cannot be carried out, with- 

 out slowly increasing the consistency of the parts restored. 



All living bodies, and especially those in which internal heat is 

 developed and maintained throughout life, continually have a part 

 of their humours and even of their bodily tissue in a real state of de- 

 composition ; hence they are incessantly undergoing real losses, and 

 it cannot be doubted that it is to the effects of degradations of the 

 solids and fluids of Uving bodies, that the various substances formed 

 in them are due. Of these, some are secreted and deposited or 

 retained, while others are evacuated by various routes. 



These losses would soon lead to degeneration of the organs and 

 fluids of the individual, if nature had not given to living bodies a faculty 

 essential to their preservation : that of making good the losses. Now 

 as a result of these continuous losses and repairs, it follows that after 

 a certain period the body cannot have in its parts any of the molecules 

 which originally composed it. 



It is known that the repairs are effected by means of nutrition ; 

 but they are more or less complete according to the age and state of 

 the organs of the individual, as I remarked above. 



Besides this inequality in the relation of losses to restorations accord- 

 ing to the ages of the individuals, there exists another which is very 

 important, and which yet appears to have received no attention. It 

 concerns the constant inequaUty between the substances assimilated 

 and fixed by nutrition, and those which are liberated as a result of 

 the continual degradation above mentioned. 



I have shown in my Recherches (vol. ii., p. 202) that the cause of 

 this inequality is as follows : 



Assimilation {the nutrition resulting from it) always provides more 

 solid jarinciples or substances, than are removed or dissipated by the 

 losses. 



The successive losses and repairs, which never cease in living bodies, 

 have long been recognised ; and yet it is only during the last few years 

 that the conviction has grown that these losses are due to degradations 

 continually being undergone by the fluids and even the solids of the 

 body. Some people still have a difliculty in believing that the forma- 

 tion of the various secretions is the result of these degradations and 

 changes or combinations always going on in the essential fluids of living 

 bodies : but this fact I have already established.^ 



Now if it is true, on the one hand, that the losses of the body consist 

 less of solid, earthy and concrete substances than of fluid substances 

 and especially volatile substances ; and if, on the other hand, it is also 



> Mémoire de Physique et d'Histoire naturelle, pp. 260-263 ; and Hydrogéologie, 

 pp. 112-115. 



