PECULIAR STATE OF LIVING MATTER. 329 



combination. This different manner of combination gives 

 rise to certain physical peculiarities, especially in density of 

 substance, which at first sight seems to constitute a deep 

 chasm between the two groups of bodies. Inorganic or 

 inanimate natural bodies, such as crystals and the amorphous 

 rocks, are in a state of density which we call the firm or 

 solid state, and which we oppose to the liquid state of water 

 and to the gaseous state of air. It is familiar to every one 

 that these three difierent degrees of density, or states of 

 aggregation of anorgana, are by no means peculiar to the 

 different elements, but are the results of a certain degTee 

 of temperature. Every inorganic solid body, by increase of 

 temperature, can be reduced to the liquid or melted state, 

 and, by further heat, to the gaseous or elastic state. In the 

 same way most gaseous bodies, by a proper decrease of 

 temperature can first be converted into a liquid state, and 

 further, into a solid state of density. 



In opposition to these three states of density of anorgana, 

 the living body of aU organisms — animals as weU as plants 

 — is in an altogether peculiar fourth state of aggregation. 

 It is neither solid like stone, nor liquid like water, but pre- 

 sents rather a medium between these two states, which may 

 therefore be designated as the firm-fluid or swollen state of 

 aggregation (viscid). In all living bodies, without exception, 

 there is a certain quantity of water combined in a peculiar 

 way with sohd matter, and owing to this characteristic 

 combination of water with solid matter we have that 

 soft state of aggregation, neither solid nor liquid, which 

 is of great importance in the mechanical explanation of 

 the phenomena of life. Its cause lies essentially in the 

 physical and chemical properties of a simple, indivisible, 



