658 What is an Organism ? [November, 
of animal and vegetable life which are entirely homogeneous 
in their structure. Such beings would, by the definition of 
Aristoteles, be excluded from the world of life and classed 
as inorganic matter. Hence this definition, able and striking 
as it is, involves not the essence of the organic, but merely a 
prominent attribute of its higher forms. Dr. Roux also 
points out that this definition leaves out of account the 
activating principle, th e (( encheiresin natures ” which holds 
this complex of implements together. 
Self-consciousness has been suggested as the common 
characteristic of the organic world. Here, however, we 
encounter a twofold difficulty : we recognise self-conscious- 
ness in ourselves, and infer its presence by analogy in other 
animals. But we cannot demonstrate it to the satisfaction 
of dissidents in the lower animals and in plants. Some in- 
vestigators even claim it as the exclusive prerogative of man. 
On the other hand, there are thinkers who maintain that 
even the inorganic world is not absolutely unconscious. It 
is easier to rejeCt this supposition than to meet it with a 
formal disproof. Hence we cannot accept self-conscious- 
ness, or, indeed, any psychic function as the characteristic 
of the organic. 
A mathematical distinction in structure has been sug- 
gested. It has been said that an organism and its parts are 
bounded by curved surfaces, whilst inorganic matter, when 
it becomes individualised, is included within plane surfaces, 
terminating in right lines, as we see in crystals, — the globular 
shape which liquids assume when in small portions, — being 
the “ point of indifference” from which crystal and organism 
branch out in different directions. Here, however, we find 
in the lower forms of life, deviations which are fatal to the 
generality of this law. If we look at the magnified figure 
of the skeleton of Xiphacantha , as given by Sir Wyville 
Thomson, we find a structure presenting the lines and 
angles of a crystal. Nor do the different laws of symmetry, 
observed as prevailing respectively in organisms and in 
crystals, form the basis of a trustworthy definition. Five- 
sided symmetry is indeed unknown among crystals, but this 
faCt is insufficient. It may further be said that a crystal if 
broken carefully is resolved into a number of smaller crystals 
of the same form, or at least into solids of some definite 
plane figure, whilst an organism if crushed or broken yields 
mere irregular fragments. Still, we must remember that 
certain polyps can be multiplied by section, each part 
becoming a distinct individual. Some authorities have 
attempted to find a characteristic of organisms in so-called 
