142 Phenothiazine—A Remarkably Efficient Anthelmintic
Samples of faeces were collected for the purpose of making a composite
count, and all of the lambs were weighed on each of the four occasions when
dosing was carried out. Particulars are set out in Table III and demonstrate
the effect of the drug during one month in bringing about an increase in weight
of 2.2 lb. per head over and above the gain in weight of the untreated controls.
Experiment No. 3.—Concerns an outbreak of parasitic gastritis among a
flock of 91 lambs of which 36 had already died before the experiment began.
The opportunity was afforded at the time that the diagnosis was made of
examining the contents of the stomach of one of the lambs which had died of
parasitic gastritis, and the infestation was found to comprise 20,750 0. circum-
cincta, 4,550 T. axei and 220 H. contortus.
The flock was then divided at random into two equal groups of 28 lambs ;
members of one group being given a dose of 20 grammes of phenothiazine in the
form of a draught, without the additional substances used by Swales and the
other group were kept as an undosed control. Weights and composite egg
counts were made on the first and on two subsequent occasions and are shown
in Table IV.
The result obtained in this observation was very remarkable in that the
dosed sheep made an increase of 12 lb. per head over and above the increase in
weight of the controls during the six weeks of the trial, representing a total
increase of 336 lb.
Experiment No. 4.—There had been several deaths from parasitic gastritis
among this flock during an outbreak of the disease which had occurred some
twelve weeks previously. A post-mortem examination carried out at that time
had shown the following parasites to be present; 23,940 O. circumcincta,
1,330 T. axei and 1,330 larvae in the stomach, and in the small intenstine,
20,640 T. vitrinus, 1,290 C. curticei, 430 C. oncophora, 5,160 N. filicollis and
2,580 larvae. About 20 lambs had died and the remainder of the flock made a
more or less satisfactory recovery before the test dosing was carried out on
October 31st.
On this occasion the 30 poorest lambs were taken out of the flock of 400 ;
these individuals were then selected in order, proceeding from the poorest to
the best member of the group ; two out of every three were dosed with 30
grammes of phenothiazine in the form of capsules, and the third was kept as an
undosed control: all were weighed. The results, which are given in Table V,
show an average increase during the three weeks observational period of 2.1
lb. per head among the treated lambs, over and above the average increase per
head of the undosed lambs.
Experiment No. 5.—K. D. Downham of the Harper Adams Agricultural
College reported an observation on eight lambs suffering from parasitic gastritis
in which during the first six days after treatment the four dosed lambs made an
average gain of 5.5 lb. each, whereas the four undosed controls made an average
gain of only 1.5 lb.
EFFECT OF THE DOSING OF HEALTHY BUT INFECTED LAMBS.—The follow-
ing few observations were carried out on healthy lambs to ascertain whether
the removal of a relatively slight infestation of parasitic worms, not sufficient
to cause obvious symptoms of disease, might bring about an increased rate of
growth.