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 amoebae 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.