ABSTRACTS
339
A nicotine compound (Black Leaf Powder) given in single dose removed all the
worms from forty-five pullets infested with adult worms. However, the powder may
not be 100 per cent efficient under all conditions. Quarter pound powder was mixed in
5 lbs. mash for every hundred birds. Feed was withdrawn from the birds the evening
before treatment. The following morning mash was given which they readily took.
The author maintains that continuous feeding of tobacco dust in mash to prevent
ascarid infestation is ineffective. The feeding of the dust for four weeks to older birds
was less effective than a single treatment with nicotine powder. [H. D. S.]
The use of nitric acid in the serological diagnosing of cattle trypanoso-
miasis. JONES, E. R. (Vet. Rec. 48, 602-605.)
PRECIPITATION of excess of euglobulin produced in trypanosomiasis has been noted
by this author by employing twenty different chemicals. Eight hundred and fifty-
seven tests, based on the theory of precipitation of serum euglobulin excess in trypano-
somiasis, were carried out to demonstrate the specific nature of reaction yielded by the
use of nitric acid. Tests were performed with the technique employed by Bennett
and Kenny (1928—Jour. Comp. Path & Therap., 41, 341) i.e., one drop of clear serum
added to 1 c.c. of the reagent; the drops being added with a Dreyer's pipette. This
gave an equivalent dilution of 1 : 25. Different concentrations of nitric acid (1.8 per
cent, 1.5 per cent and 1.3 per cent W/V HNO 3 ) were used and the time reading of
reactions was noted. Of 249 tests in which the reaction was allowed to proceed to
exactly one hour the following result was noted:—With 1.8 per cent, forty-five per cent
of the cases gave positive reaction; with 1.5 per cent, and 1.3 per cent, 21 per cent
gave doubtful reaction ; while 34 per cent were negative with latter concentrations.
One hundred and thirty tests were carried out in which the reaction was noted imme-
diately after 1.8 per cent W/V HNO 3 was added and it was observed that 51 per cent
of the cases gave positive while 49 per cent gave negative or doubtful reaction.
It is indicated that application of nitric acid as a serological test is a modification of
the xanthoproetic reaction for proteins. The precipitate produced in mercuric chloride
test is in the form of metaprotein, while those with nitric acid, according to the author,
is euglobulin itself.
It has been pointed out that the reaction is seldom given in the early stages of infec-
tion when trypanosomes are present in the blood—in which case direct blood examina-
tion suffices, but it was conclusive afterwards in chronic or " latent " infections when
parasites could not be detected in the blood. It has been suggested by the author
that further tests would have to be carried out to determine (a) the period of infection
before the test becomes positive, and (b) the specificity, if any, of the test in relation to
other diseases.
Addition of 0.025 per cent of phenol to the serum as a preservative did not alter
the reaction which could still be obtained seven to eight days after the serum had been
collected. Affected cases used by the author in his series of tests were known to be
infected with trypanosomes belonging to Vivax, Congolense and Brucei groups.
[H. N. R.]