520 FLUIDITY OF ORGANIZED BODIES. 



are held together with great force, and endure 

 for a much longer time than trees, which consist 

 of ternary combinations of more active elements. 

 For the same reason, animal bodies that are 

 formed of three elastic gases, united in various 

 proportions with carbon, are more volatile and 

 destructible than wood, after the affinities of 

 life have ceased. In other words, minerals are 

 more solid and fixed than plants, because they 

 are formed of more gross and inert materials ; 

 while trees are more solid and durable than the 

 animal tissues, because the first are composed 

 chiefly of water, with carbon, and the latter of 

 air, water, and carbon. 



So essential are fluids to the existence of or- 

 ganized bodies, that they constitute nearly the 

 whole of their substance during the embryotic 

 state, especially in the egg and foetus of animals. 

 But the proportion of fluids to that of solids, 

 varies in different species, and at different 

 periods of their growth, being about ten to one 

 during early life in the human body, and six to 

 one in old age. According to Richerand, they 

 are as three to one in trees ; but they are much 

 more abundant in the annual and more succulent 

 plants, as also in the newly formed parts of 

 trees ; while it is worthy of notice, that the affi- 

 nities of life are always most active in those 

 parts which receive the greatest amount of fluids, 

 such as the medullary and muscular tissues of 



