, -28- 
*~ith cube dip in the Juriin area, and 150,000 in that of Funo. The 
dips r-ere obtained either from an extract prepared by soaking the 
chopped: roots in ^ater 48 hours, or from a ponder ground so fine 
that 85 percent passed a 0.074 mm. -mesh sieve. In 1936 J. F. Mitchell 
stated that the ponder yielded a dip that was more saponaceous, and 
therefore penetrated better, than" that from the extract. Dips made 
,- ith the powder did not keep more than. 48 hours, ^hereas those made 
v- ith the extract kept a week. The addition of 1/2 pound of soa-n per 
100 gallons vjps recommended, and also that of 1/2 pound of sodium 
carbonate to counteract the hardness of the ^ter. For complete con- 
trol of the -oare sites, sheep usually reouired 2 dips, ~uth about a 
fortnight interval, twice a year, except in serious infestations, "-hen 
a third pair of dips wes necessary. The effective concentrations of 
ground cube root containing 1 6. "8* percent of rotenone,. and of extract 
containing 5.5 percent of rotenone verc , respectively, 1:2,000 and 
1:10,000. ^e ground root and the extract --'ere eoualiy effective and 
'-ere in no vay inferior to other dips. 
■•-■'. f 
Edwards (79) in 1938, in e popular account -of rotenone-containing 
insecticides, stated that they are effective against the sheep ked. 
Stewart ( 264 ) in 1039 reported tests of 5 dips for the control of 
ticks on sheep in Scotland; (A) A plain derris din (solution of 
derris extract), (3) derris-carbolic paste, (C) derris-carbolic— ^ogI fa1 
p?ste, (D) arsenic-carbolic paste, and (3§) a commercial tick-dip (High- 
land Tick Paste containing both arsenic and- derris). Those derris dips 
that did not contain arsenic possessed negligible tick-deterrent pro- 
perties. It r^as found that such dips are efficient tick-killing a-ents, 
but under the conditions of the above test thev showed little -value 
as repellents. -his finding is not in agreement r-ith the results of 
critical small-scale tests, and MacLeod suggests (in a personal com- 
munication to 3. C. Hoark) that the discrepance lies in the difference 
in immersion time. The average hill shepherd immerses his sheep for 
something less thFn 15 seconds. The duration of the actual immersion 
period appears to be more important ™ith derris than ^ith other dips. 
The most satisfactory dip reported by Ste^rt proved to be dip E, 
nhich showed a marked deterrent effect 2 <-ee!:s after use. Dusting 
r.ovrly born lambs tfith a derris preparation gp^e better results than 
dipping in a diluted derris extract, or tr atir.g with an oily smear 
containing derris. 
The New Zealand Department of Scientific and. Industrial Research 
(218) in 1940 reported th~t sheep-dip investigations on sheer) infested 
T "ith keds and lice, and treated in dips. of "vsrious compositions, in- 
dicated that all the prepr rations containing arsenites, phenols, ar.d 
rotenone ^ere effective against adtilt keds, but in order to be thoroughl 
effective the toxic influence should-be protracted long enough to deal 
also with the keds that emerge from the pupae. Incomplete trials 
indicated that derris possesses value for riving this delayed action. 
