1 8 2 NO THING ALIVE IN E VER Y PART. 



In man, and the higher animals, the free portions of the 

 nails and hair, the outer part of the cuticle, and a portion of 

 the dental tissues, are evidently lifeless. These free por- 

 tions have grown, but have now ceased to grow, though 

 growth may be active at the deep parts of these textures 

 which are near the blood-vessels. The waste and removal 

 of some of these textures is indeed compensated to a great 

 extent by the addition of new matter, the components of 

 which are re-arranged in such a manner as to form the tex- 

 ture in question. This is effected through the agency of 

 living particles which grow and multiply in the situation 

 indicated. 



Of the internal tissues of man and animals, a great part 

 is also in a non-living condition, and it therefore becomes 

 necessary in all inquiries concerning the nature of the 

 changes and actions taking place during life, to determine 

 at the outset what parts of these beings are in a living state, 

 and what parts have already ceased to live, although they 

 may perform important service of a passive kind, and even 

 be connected with, or seem to pass into, the matter that is 

 actually alive. 



Even in the smallest organisms which exhibit the sim- 

 plest characters, as well as in every texture of the most 

 highly complex beings, we can demonstrate two kinds of 

 matter, differing in very important particulars from one 

 another; or perhaps it would be more correct to say, 

 matter in two different states, manifesting different properties, 

 and exhibiting differences in appearance, chemical com- 

 position, &c., and physical characters. This fact is essential 

 and invariable, and although by calling everything entering 

 into the composition of a living being by the same name, all 



