One of these forms is _Heteromita rostrata_, which, it will be
remembered, in addition to a front flagellum, has also a long fiber or
flagellum-like appendage that gracefully trails as it swims. At
certain periods of its life they anchor themselves in countless
billions all over the fermenting tissues, and as I have described in
the life history of this form, they coil their anchored fiber, as does
a vorticellan, bringing the body to the level of the point of
anchorage, then shoot out the body with lightning-like rapidity, and
bring it down like a hammer on some point of the decomposition. It
rests here for a second or two, and repeats the process; and this is
taking place by what seems almost like rhythmic movement all over the
rotting tissue. The results are scarcely visible in the mass. But if a
group of these organisms be watched, attached to a small particle of
the fermenting tissue, it will be seen to gradually diminish, and at
length to disappear.

Now, there are at least two other similar forms, one of which,
_Heteromita uncinata_, is similar in action, and the other of which,
_Dallingeria drysdali_, is much more powerful, being possessed of a
double anchor, and springing down upon the decadent mass with
relatively far greater power.

Now, it is under the action of these last forms that in a period
varying from one month to two or three the entire substance of the
organic tissues disappears, and the decomposition has been designated
by me "exhausted"; nothing being left in the vessel but slightly
noxious and pale gray water, charged with carbonic acid, and a fine,
buff colored, impalpable sediment at the bottom.

My purpose is not, by this brief notice, to give an exhaustive, or