usual manifestations of life; these returned when the organism was
removed from the unfavorable conditions, and with this or preceding it
the organisms, if visibly altered, regained the usual form and
structure. We may regard this as disease and recovery. In the disease
there is both the injury or lesion and the derangement of vital
activity dependent upon this. The cause of the disease acted on the
organism from without, it was external to it. Whether the injurious
external conditions act as in this case by a change in the surrounding
osmotic pressure, or by the destruction of ferments within the cell,
or by the introduction into the cell of substances which form stable
chemical union with certain of its constituents, and thus prevent
chemical processes taking place which are necessary for life, the
result is the same.

The experiments with the amoebæ show also two of the most striking
characteristics of living matter. 1. It is _adaptable_. Under the
influence of unusual conditions, alterations in structure and possibly
in substance, may take place, in consequence of which the organisms
under such external conditions may still exhibit the usual phenomena.
The organism cannot adapt itself to such changes without undergoing
change in structure, although there may be no evidence of such changes
visible. This alteration of structure does not constitute a disease,
provided the harmonious relation of the organism with the environment
be not impaired. An individual without a liver should not be regarded
as diseased, provided there can be such an internal adjustment that
all of the vital phenomena could go on in the usual manner without the
aid of this useful and frequently maligned organ. 2. It is
_individual_. In the varying degrees of exposure to unfavorable
conditions of a more serious nature some, but not all, of the
organisms are destroyed; in the slight exposure, few; in the longer,