THE CONSTITUTION OF MATTER. 19 
up of molecules in which the atoms are grouped in prisms, in 
pyramids, in a word, in polyhedra more or less many-sided, 
but always of perfect regularity; so that, in this case, the 
differentiation is regulated with marvelous harmony. 
We must now rise another degree, and pass from in- 
organic matter to living matter. What is it that distin- 
guishes the latter from the former? When we make the 
answer depend on the results of direct experiment, nothing 
is easier than to establish the differential characteristics of 
living matter. In the first place, it is organized, that is, the 
anatomical elements, instead of being homogeneous and 
symmetrical in all points of their mass, are composed by 
the association of a certain number of different substances, 
in which carbon predominates, and which are termed im- 
mediate organic principles... Then these elements grow. 
At no time the same throughout, as to the substance which 
makes them up, they are in a state of unceasing molecular 
renewal, of constant metamorphosis, of simultaneous and 
continuous assimilation and disassimilation. Besides, the 
various properties these elements may exhibit, contractility, 
neurility, and so on, are, in consequence of the growing 
state that characterizes them, in so unstable a condition of 
equilibrium that the slightest variation in the surrounding 
medium is enough to occasion some change in the expres- 
sion of their activity ; in other words, they have excessive 
excitability and irritability. Such, at least, is the region 
within which physiology is limited; but the fact which it 
does not clearly enough bring out, yet the thing which is 
the distinctive mark of life, is the harmonious seeking for 
each other of all these vital monads, the disposition of 
1 “The structure of chemical compounds is subject only to mathemati- 
eal laws, which laws do not control that of organized matter. In germs 
and their products there exists a want of symmetry in their axes, which 
indicates a formative purpose, or, more properly, a creative omnipotence.” 
—Gaunin, “ Architecture of the World of Atoms,” p. 8. 
