66i 
1882.] What is an Organism ? 
materials. One inorganic process, indeed, — to wit, flame, 
or rather, combustion — has the power of assimilating foreign 
matter, and, indeed, makes, in various important points, the 
nearest approach to the vital process, as we shall shortly see. 
The power of assimilation may exist in very varied degrees, 
and upon them the permanence of such process will greatly 
depend. A process may assimilate less than it consumes, 
as in an ill-fed animal. Here the end cannot be far off. Or 
it may assimilate exactly as much as it consumes, in which 
case it can never extend, and is always liable to extinction 
on the least disturbance. Or, lastly, the assimilation may 
be in excess of all immediate demands. This is and must 
be the case in every permanent process. Hence, we find 
that along with assimilation the next universal requirement 
of organic beings is super-compensation of daily waste. 
We find, too, in organisms, the power of self-regulation. 
The assimilation must depend on the degree of consumption. 
As the waste of tissue — the transformation of matter — 
increases, the introduction and assimilation of nutriment, in 
the widest sense of the word, must increase also. If in- 
creased work is not accompanied by increased hunger, or if 
nutriment is not attainable, or if when procured it cannot be 
assimilated, we have as the result the cessation of the 
process, or death. 
But another essential point for the permanence of a vital 
process is the elimination of what has been consumed, i.e., 
of the waste-produCts of the process. Were this process of 
elimination to go on at one uniform rate, then if the con- 
sumption were increased, there would be an accumulation 
of effete matter, which would reaCt destructively upon the 
process itself. 
It is curious to see how both these features of self-regula- 
tion are observed in combustion as well as in life. The 
more briskly the flame burns, e.g., when urged by a current 
of air, the more abundant must be the supply of fuel, unless 
the combustion is to come to a speedy end. The more fuel 
is supplied the more ashes are accumulated, but under 
favourable circumstances the more readily they are dissipated 
by the increased currents of air. 
Hence we see that when, in the language of poetry, flame 
has been always taken as a symbol of life ; when we hear 
speak of it as “ hungry,” “ devouring,” &c., there is scarcely 
a departure from literal truth. 
There are, however, certain distinctions between life and 
flame which Dr. Roux has not brought forward. Flame 
will go on for ever as long as supplied with appropriate 
