16 BULLETIN 245, U. S. DEPARTMENT OF AGRICULTURE. 
that the larvicidal value varies with the amount of powdered helle- 
bore used, but when applied at the rate of one-half pound or more to 
8 bushels of manure it will be efficient. It is not known how helle- 
bore acts as a larvicide. At present no information is available as 
to whether it has any effect on the eggs or pupe of the house fly. 
The effects of the presence of fly maggots in a pile of manure is very 
strikingly shown by comparing figures 2 and 3 of Plate I. The pile 
treated with hellebore has remained normal in shape and appearance 
(Pl. I, fig. 3), while the maggots have worked the untreated pile 
shown (Pl. I, fig. 2), the manure being finely divided and the 
pile scattered by the feeding and migration of the larve. 
The bacterial counts of manure in the cages (Table VI) treated 
with 1 per cent sulphuric-acid extracts of hellebore showed no bac- 
tericidal effects. 
The bacterial counts of the open piles (Table IV) did not show 
any consistent action, either stimulating or bactericidal. During the 
season’s work nitrites and nitrates were detected only in open-pile 
experiments 53, A,B, C, and D, which were treated with hellebore, 
and it is therefore apparent that the hellebore extract is not toxic 
to the nitrifying organisms 1n this environment. 
Three series of temperatures taken daily of control piles and those 
treated with pyrethrum, pyridine, and hellebore further indicated 
that there was no permanent injury to the bacteria present in the 
piles treated with the last substance. In the first series the tem- 
perature was 13° below the control on the second day, but on the third 
day was again the same as the control. Neither of the other series 
showed any depression of temperature at the start, and the piles 
seemed to undergo a normal fermentation, indicating, as do all the 
data, that the treatment with hellebore does not reduce the fertiliz- 
ing value of the manure. | 
The chemical data on both the cage and open-pile experiments 
show that the manure was unaffected by the hellebore treatment. 
When 1 per cent sulphuric-acid extracts were used in the cage experi- 
ments at Arlington, a reduction in alkalinity due to the added acid 
was found. It is, therefore, evident that powdered hellebore can be 
applied, using one-half pound to 10 gallons of water, without injuring 
the fertilizmg value of manure as determined by chemical and 
bacteriological examination. Furthermore, a laboratory test has 
shown that hellebore readily decomposes In manure. <A sample of 
manure treated with hellebore at the rate of one-half pound per 
8 bushels when tested microscopically and colorimetrically gave 
positive results, but after 30 days’ fermentation both were 
negative. 
The alkaloidal content of the commercial green and white hellebore 
is known to vary from about 0.2 per cent to 0.9 per cent of total 
alkaloids! In Table IV, series 53, the hellebore used was of known 
1 Data obtained from Insecticide Laboratory, Bureau of Chemistry, U.S. Department of Agriculture. 
