216 DARWINISM TO-DAY. 



cles, or, as they are in most of the micromeric theories, as living 

 particles which are destroyed with the death of the organism 

 which they compose. In this latter type of assumption the units 

 are, according to some theories, all of the same nature, all exer- 

 cising an equal influence in determining the character of a devel- 

 oping organism (Spencer, Haacke, His, Cope) ; or they are, as 

 assumed in other theories, of various character and charged with 

 various functions. This latter kind of unit is held by some authors 

 to be actually representative either of ancestral plasmas (Weismann) 

 or of the actual body-cells of the parent (Darwin, Galton, Brooks, 

 Hallez), or of elementary characteristics and functions of the 

 organism (Nageli, Kolliker, de Vries, O. Hertwig), or at the same 

 time of both body-parts and elementary characteristics (Weismann's. 

 latest theory). 



Buffon's theory assumed that "the substance of which organisms 

 are composed differs essentially from that which composes the 

 Buffon's inorganic bodies. Organisms are composed of special 



theory. particles, the organic molecules. These molecules are 



universal and indestructible: universal in that they exist everywhere 

 where life has access, indestructible in that death and the dissolution 

 which follows destroy the organisms, break down the molecular com- 

 binations which constitute them, but do not reach the molecules 

 themselves. These are only separated, put at liberty, but remain 

 ready to enter into new groupings. While they cannot be de- 

 stroyed, neither do they increase in numbers. They form nothing 

 actually new, either spontaneously, or by means of old ones, so- 

 that, measured by these organic molecules, the total quantity of life 

 in the universe is invariable" (Delage). Nearly a hundred years 

 later Bechamp (1883) proposed a theory similar to Buffon's in 

 which he assumed the composition of organisms out of minute 

 elementary living particles called microsymes. Like Buffon's 

 organic molecules they are indestructible, and they are strewed in 

 innumerable numbers through earth, air, and water. They owe their 

 origin to special creation by God. 



Of the non-immortal kind of micromeres Spencer's physiological 

 units represent a general type favoured by numerous theorists L 

 namely, living units all of the same nature and active because of 

 their polarity, their form and molecular forces, or their vibratory 

 motion. Spencer's physiological units are active because of their 

 polarity, but the annular atoms of Dolbear's theory and the 

 plastidules of the slightly varying theories of Haeckel, His, Cope, 

 and others, owe their active properties to their vibratory motion. 



According to Spencer (1864), there exist between the cells 

 (morphological life-units) and the molecules which compose them 



