2
(ii) By communicating the disease in a somewhat similar manner to that
in which it is naturally contracted, viz., by small repeated doses of the
hæmatozoon in water.
The chemicals made use of during these experiments were:
(a) Arsenic.
(b) Tri-iodide of Arsenic and Bin-iodide of Mercury.
In the first instance, although the latent period was not lengthened, the
course of the disease was undoubtedly modified, only a few hæmatozoa being at
any time in the blood; and although the disease had run for some weeks, the
animals still maintain a fair condition. Owing to the reasons given below, the
drugs administered were insufficient to withstand the severe and unnatural test
of subcutaneous inoculation. As a lengthened period is required to communi-
cate Surra by the second method, the experiments are not yet concluded; but
the results, as yet obtained, warrant one in believing that they will be suc-
cessful. It appears that animals suffering from Surra have a greater tolerance
of Arsenic than healthy animals, when the drug is administered for a lengthened
period, as in the above experiments. Difficulty was experienced in getting the
horses, accustomed to be watered at a river or tank, to take the drug (in water),
or even pure water from a bucket. No such difficulty occurred in treating
previously recorded Surra-cases received from Bombay, where horses had always
been used to the latter method. During an acute attack of a disease only
lasting a few days, it is easy to administer drugs by drenching; but in the
treatment of Surra, when it is necessary to administer medicines two or three
times daily for a period of some weeks, drenching is out of the question, as any
unnecessary disturbance of the animal, and possible injury to the mouth is
prejudicial, and would certainly retard recovery.
5. Several interesting physiological problems have been worked out relat-
ing to the ingestion and excretion of Nitrogen during health, and the course of
the disease (Surra) under treatment. The results of these will be published when
the cases are complete.
II.
RAT SURRA.
A.—Historical Account.
1Lemsin 1877 detected organisms in the blood of the rat. Two species of
Rat harboured these parasites, Mus decamanus and Mus rufescens. But although
Lewis examined the blood of a large number of mice, he never detected
organisms, nor did he see them in any animals other than rats. He found the
organism present in rats examined in Calcutta, also at Simla, elevation 7,500 ft.
The animals kept by him in cages, for weeks remained to all appearance in
perfect health.
2. 2 Wittieh and ³ Koch in 1881 described similar organisms in the blood
of hamsters in Germany.
3. 4 Crookshanh in 1886 found that 25 per cent of rats taken from the
London sewers contained these active organisms.
4. 5 Vandyke Carter's observations on rats included Mus decumanus and
Mus rattus. 12 per cent of the rats examined presented the organism in their
blood. A few examples examined of Mus bandicottus (?) and of Sorex, species
Lewis, l T.—Flagellated organisms in the blood of healthy rata.
Appendix 14th Annual Report of San. Com. with Gov. of India. 1878.
WIttich 2 .—Spirillen im Blut von Hamstern.
Centralblt.f.Med.Wiss.l881.No.4:.
Koch 3 .—Mitteilungen aus der Kaiserlich Gesundh. 1881.
Crookshank, 4 E. M.—Flagellated Protozoa &c.
Journal Royal Micros. Soc. Nov. 1886.
Carter, 5 H. V.—Scientific Memoirs by Medical Officers of the Army of India, Vol. IV. 1887.
p. 50.