of organic tissue--the sending back into nature of the only material
of which future organic structures are to be composed.

I have said that there can be no question whatever that _Bacterium
termo_ is the pioneer of saprophytes. Exclude _B. termo_ (and
therefore with it all its congeners), and you can obtain no
putrefaction. But wherever, in ordinary circumstances, a decomposable
organic mass, say the body of a fish, or a considerable mass of the
flesh of a terrestrial animal, is exposed in water at a temperature of
60° to 65° F., _B. termo_ rapidly appears, and increases with a simply
astounding rapidity. It clothes the tissues like a skin, and diffuses
itself throughout the fluid.

The exact chemical changes it thus effects are not at present clearly
known; but the fermentative action is manifestly concurrent with its
multiplication. It finds its pabulum in the mass it ferments by its
vegetative processes. But it also produces a visible change in the
enveloping fluid, and noxious gases continuously are thrown off.

In the course of a week or more, dependent on the period of the year,
there is, not inevitably, but as a rule, a rapid accession of spiral
forms, such as _Spirillum volutans_, _S. undula_, and similar forms,
often accompanied by _Bacterium lineola_; and the whole interspersed
still with inconceivable multitudes of _B. termo_.

These invest the rotting tissues liked an elastic garment, but are
always in a state of movement. These, again, manifestly further the
destructive ferment, and bring about a softness and flaccidity in the
decomposing tissues, while they without doubt, at the same time, have,
by their vital activity and possible secretions, affected the