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case 6 (appendix F), and defibrinated, it contained the parasites of surra innumerable in every
drop, and very active. It was then thoroughly mixed with three times its bulk of water from
the well from which the horses drink, and allowed to stand covered in the pharmacy until this
morning. Twenty-four hours after it was thus treated, I stirred it well up and examined some
of it by the microscope ; no parasite could be found in it. It had no bad smell, or any sign of
decomposition. Five ounces of the blood and water mixture were now added to 35 ounces of
fresh water, and given as a draught to No. 72. Twenty ounces of the blood and water mixture
were mixed with twenty ounces of fresh water, and given as a draught to No. 302.
October 18th —Ten days have elapsed without any ill effects to these horses. They have
no outward sign of surra and no blood parasite. Judging from the incubative stage in the
other horses, I suppose the result of this experiment is negative. I leave for Simla to-morrow
and request to be informed should one of these ultimately prove affected.
October 30th.—I have heard nothing more of these cases, therefore conclude they prove the
negative. The failure goes a long way to prove that the disease is communicated by the
parasite, and not by any chemical change in the blood independent of the parasite, as is
contended by those who disbelieve in the theory of living organic germs causing specific diseases.
APPENDIX I.
Surra transmitted from horse to dog.
October 5th, 1880.—A pariah dog and a bitch were inoculated in two separate parts of the
neck by the hypodermic injection of two separate drams of blood containing the parasite,
freshly drawn from the jugular of a horse suffering from surra. They are also allowed to drink
the blood and eat the flesh of a horse which died of the disease. The dogs are thin, but they
appear in good health, and I could find no parasite in their blood or anything abnormal. The
bitch has a sucking pup about a month or six weeks old, in good health and free from blood
parasites also; he has not been inoculated, and I have directed the mehter in charge not to give
him any blood or flesh. The mehter himself eats the flesh of horses which die of surra after it
is cooked and salted and peppered.
October 16th —Blood of the dog examined; it contains a very large increase of white
corpuscles, but no parasite could be found in three drops examined.
Very few parasites of surra found in the blood of the bitch. I was about giving up the
search before I found one. Her blood has also a large increase of white corpuscles. Both the
dog and the bitch are more thin than they were and they look miserably ill, with a catarrhal
discharge from the eyes, but I do not find the mucous membrances yellow nor any petechiae,
such as horses have in surra.
The blood of the pup is swarming with active surra parasites, he is thinner too, for he gets
little milk from his mother, but he is playful and shows no sign of illness. The mehter in
charge declares that the pup has had no blood or flesh, nothing but his mother's milk; but I
have strong reason for doubting that; and this experiment alone cannot be relied upon to prove
that the parasite may be transmitted through the mammary gland with milk, though it may
ultimately serve to corroborate future experiments in that direction.
October 22nd.—Arrived at Simla this morning with the pup. Principal Veterinary
Surgeon F. F. Collins called in the afternoon and saw the parasites in the blood in countless
numbers, but they are not so active as they were.
October 23rd.—Mr. Collins called again this morning and found every red corpuscle of the
blood quivering from the motion of the parasites; there seemed, as he remarked, as many parasites
as there were of red corpuscles. Mr. Collins noticed them separating the corpuscles from the
others. It occurred to me that the cold at Simla was the reason for their inactivity. At Dera
Ismail Khan the metal of my microscope felt uncomfortably hot very often when I was working
at it, whereas here it feels cold. I therefore put a slide with the blood this morning upon a
heated plate under the microscope and it had a wonderful effect upon the parasites in making
them more active.
October 25th.—Veterinary Surgeon Poyser, of the Carabineers, called to see the parasites.
Several drops of fresh blood were examined, but very few were found; only about 10 or 15 in each
drop, and they were very inactive, but larger in size than they were on the 23rd.
October 26th.—Dr. Lewis, Special Assistant to the Sanitary Commissioner, and one of the
best authorities upon blood parasites, called this morning, examined the parasites, which are in
number and appearance as they were yesterday. He thinks they are of the same class or family
of organisms as what he found in the blood of rats and described in the Microscopical Journal,
January 1879, though they do not appear exactly the same. He believes they are of the lowest
order in the animal kingdom.
October 30th.—This morning I met Surgeon-General Cunningham by appointment at
Dr. Lewis's laboratory for a further examination of these parasites; tut though six drops of fresh
blood from the pup were examined, not one parasite could be found. The dog is growing and
improving in condition; he shows no sign of ill-health. As I am under orders to proceed to