rvations made, not only on their efficiency in killing the maggots
but also as to their effect on the chemical composition and bacterial
flora of the manure. The object was to find some cheap chemical which
would be effective in destroying the fly larvae and at the same time
would not reduce the fertilizing value of the manure.

TREATMENT WITH HELLEBORE.

Of the numerous substances tried, the one which seems best to fulfill
these conditions is powdered hellebore.[10] For the treatment of manure a
water extract of the hellebore is prepared by adding 1/2 pound of the
powder to every 10 gallons of water, and after stirring it is allowed to
stand 24 hours. The mixture thus prepared is sprinkled over the manure
at the rate of 10 gallons to every 8 bushels (10 cubic feet) of manure.
From the result of 12 experiments with manure piles treated under
natural conditions it appears that such treatment results in the
destruction of from 88 to 99 per cent of the fly larvae.

Studies of treated manure indicated that its composition and rotting
were not interfered with. Furthermore, several field tests showed that
there was no apparent injury to growing crops when fertilized with
treated manure.

Since the solution is somewhat poisonous it should not be left exposed
where it might be drunk by livestock. It is quite safe to say that
chickens will not be injured by pecking at hellebore-treated manure.
This has been tested carefully. Hellebore can be obtained both in ground
and powdered form, but the powder gives the best results in the
destruction of fly larvae.

[Footnote 10: _Veratrum viride_ or _V. aloum_.]

TREATMENT WITH POWDERED BORAX.

Another chemical found to be even more effective as a larvicide is
powdered borax. This substance is available in commercial form in all
parts of the country. It has the advantage of being comparatively
nonpoisonous and noninflammable and is easily transported and handled.
The minimum amount necessary to kill fly larvae was found to be 0.62
pound per 8 bushels of manure, or about 1 pound per 16 cubic feet. Best
results were obtained when the borax was applied in solution, or when
water was sprinkled on after the borax had been scattered evenly over
the pile. Borax is not only effective in killing the larvae, but when it
comes in contact with the eggs it prevents them from hatching. When
applied at the rate of 1 pound to 16 cubic feet it was found to kill
about 90 per cent of the larvae,