Scientific American Supplement, No. 643 | Page 5

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 condition of the changing
organic mass. There can be, so far as my observations go, no certainty
as to when, after this, another form of organism will present itself; nor,
when it does, which of a limited series it will be. But, in a majority of
observed cases, a loosening of the living investment of bacterial forms
takes place, and simultaneously with this, the access of one or two
forms of my putrefactive monads. They were among the first we
worked at; and have been, by means of recent lenses, among the last
revised. Mr. S. Kent named them Cercomonas typica and Monas
dallingeri respectively. They are both simple oval forms, but the former
has a flagellum at both ends of the longer axis of the body, while the
latter has a single flagellum in front.
The principal difference is in their mode of multiplication by fission.
The former is in every way like a bacterium in its mode of self-division.
It divides, acquiring for each half a flagellum in division, and then, in
its highest vigor, in about four minutes, each half divides again.
The second form does not divide into two, but into many, and thus
although the whole process is slower, develops with greater rapidity.
But both ultimately multiply--that is, commence new generations--by
the equivalent of a sexual process.
These would average about four times the size of _Bacterium termo_;
and when once they gain a place on and about the putrefying tissues,
their relatively powerful and incessant action, their enormous multitude,
and the manner in which they glide over, under, and beside each other,
as they invest the fermenting mass, is worthy of close study. It has been
the life history of these organisms, and not their relations as ferment,
that has specially occupied my fullest attention; but it would be in a
high degree interesting if we could discover, or determine, what besides
the vegetative or organic processes of nutrition are being effected by
one, or both, of these organisms on the fast yielding mass. Still more
would it be of interest to discover what, if any, changes were wrought

in the pabulum, or fluid generally. For after some extended
observations I have found that it is only after one or other or both, of
these organisms have performed their part in the destructive ferment,
that subsequent and extremely interesting changes arise.
It is true that in some three or four instances of this saprophytic
destruction of organic tissues, I have observed that, after the strong
bacterial investment, there has arisen, not the two forms just named,
nor either of them, but one or other of the striking forms now called
Tetramitus rostratus and _Polytoma uvella_; but this has been in
relatively few instances. The rule is that Cercomonas typica or its
congener precedes other forms, that not only succeed them in
promoting and carrying to a still further point the putrescence of the
fermenting substance, but appear to be aided in the accomplishment of
this by mechanical means.
By this time the mass of tissue has ceased to cohere. The mass has
largely disintegrated, and there appears among the countless bacterial
and monad forms some one, and sometimes even three forms, that
while they at first swim and gyrate, and glide about the decomposing
matter, which is now much less closely invested by Cercomonas typica,
or those organisms that may have acted in