ng of the entire area of the trench. Combustible sweepings
or straw, saturated with oil, may be used for this purpose.

In fly season, trenches may be closed with seats covered down to the
ground with muslin and supplied with self-closing lids. Urinal
troughs, made of muslin and coated with oil or paint, should discharge
into the trenches.

676. In permanent camps special sanitary facilities for the disposal
of excreta will ordinarily be provided.

If necessary, urinal tubs may be placed in the company streets at
night and removed at reveille. Their location should be plainly marked
and thoroughly and frequently disinfected.

677. When troops bivouac for the night the necessity for extensive
sanitary precautions is not great; however, shallow sink trenches
should be dug to prevent general pollution of the vicinity. If the
cooking be collective, shallow kitchen sinks should be dug. If the
cooking be individual, the men should be required to build their fires
on the leeward flank of the camp or bivouac.

Before marching, all trenches should be filled in.

_PROTECTION OF CAMP OR BIVOUAC._

_General Considerations._

678. The outpost is a covering detachment detailed to secure the camp
or bivouac against surprise and to prevent an attack upon it before
the troops can prepare to resist.

679. The size and disposition of the outpost will depend upon many
circumstances, such as the size of the whole command, the proximity of
the enemy and the situation with respect to him, the nature of the
terrain, etc.

A suitable strength may vary from a very small fraction to one-third
of the whole force. For a single company in bivouac a few sentinels
and patrols will suffice; for a large command a more elaborate outpost
system must be provided. It should be no stronger than is consistent
with reasonable security.

The most economical protection is furnished by keeping close contact
with the enemy by means of outpost patrols, in conjunction with
resisting detachments on the avenues of approach.

The outpost should be composed of complete organizations.

680. In a brigade or smaller force on the march toward the enemy, the
outpost is generally formed from the advance guard, and is relieved
the following day when the new advance guard crosses the line of
outguards. In a retreat, the detail for outpost duty is generally made
from the main body. The new outpost becomes the rear guard the
following day.

681. When, as in l