1882.1 
What is an Organism ? 
659 
mechanical memory, that is, the permanence for a greater 
or less time of effedts after their cause has ceased. But this 
is a universal property of matter in accordance with the law 
of inertia. 
Organisms have also been defined as portions of matter 
individualised so as to be independent. This attribute, how- 
ever, is common just as much to every process which is 
severed by its consistence, or by other especial attributes from 
its surroundings. Stridtly speaking, independence exists 
nowhere. 
Neither can we appeal to the transformation of energy, 
whether alone or in conjunction with the transformation of 
matter. This combined adtion is to be seen constantly in 
the weathering of rocks, and the evaporation of water. 
The consistence of organisms is also not characteristic, 
though in their adtive portions it varies merely within certain 
limits, which may be a needful preliminary condition for the 
origin and maintenance of life. The percentage of water 
may range from 12 in certain seeds to 99 in some Medusidce . 
It should here be remembered that we know of no organisms 
consisting entirely of liquids or gases without the presence 
of solids. 
A certain chemical composition, common, with slight 
variation to all organisms, is probably an essential feature, 
but is yet not the essence of organisation itself, since the 
chemical constitution of animal and of vegetable protoplasm 
is probably not identical. These features being all set aside 
as not affording the wished for distinction, we come to some 
few considerations of another order. 
The first really essential characteristic of organic beings 
is sensibility, which is common to all living beings, if not to 
all their parts. It may be considered, according to Roux, as 
the faculty of organic beings when exposed to the adtion of 
heat, light, or possibly of other phases of energy, to modify 
their form in a manner which cannot be regarded as a mere 
passive transformation, due to the external adtion, but is 
possible only by exciting a certain condition consisting in an 
intensification of cohesion, or in the removal of hindrances 
to its adtion. 
Dr. Roux, however, very justly observes that we have here 
merely a special case of the general readability of all bodies. 
Still, although there are inorganic bodies, e.g., mixtures of 
chlorine and hydrogen, which on exposure to light undergo 
a chemical change and become more coherent, being con- 
densed so as to occupy less space, yet reflex movement is 
distindt to such a degree from all inorganic readtions that 
it may be regarded as a charadteristic feature. 
