The birds moved freely from the back of one animal to the other, and no doubt this is one source by which the disease is spread. This would occur with the greatest ease either with their blood-stained beaks or with their soiled feet coming in contact with a raw surface, for I have proved that a minute fraction of a drop of blood containing surra hematozoon is capable of conveying the disease to the horse if spread over a scratch in the skin of the animal.”

We see nothing improbable in this view. In fact, surra appears to us to be a wound disease, transmissible through any sort of wound, whether it be made by insects, crows, syringes, knives, or anything else, provided undried trypanosomatic blood comes in contact with the freshly wounded surface.

C. INFECTION BY INGESTION OF BLOOD OF AFFECTED ANIMALS. A number of experiments have been made to transmit surra to aņimals by feeding the blood of infected animals, and attention has already been directed to the statement that dogs and cats are alleged to become infected through eating surra carcasses. We are inclined to accept this as a possible method of transmission, but in this connection we would direct attention to the following points:

(1) It does not appear to be satisfactorily demonstrated () whether the parasites have forced their way through the intestinal mucosa (as does not seem impossible: Compare bacterial infections; tuberculosis; trichinosis; Balantidium coli, according to Strong's recent interesting results); or, () whether the hematozoa have entered the system through some intestinal wound. (2) It also does not appear in the ingestion experiments that authors have always excluded the possibility of accidental infection by insects. Infection by ingestion of blood does not at present come into very serious consideration in connection with the transmission of surra from horse to horse, unless perhaps the horses should lick fresh, bleeding fly bites, and thus accidentally smear a wound in the mouth with trypanosomatic blood."

D.? CONGENITAL INFECTION.

According to Lingard (1895, p. 12), no Trypanosoma has been found in the fetuses in case of rats, even when the gravid mother was found infected. This conclusion is based upon a number of observations, and apparently establishes the fact that, at least under normal conditions of the placenta, surra is not congenitally infectious. (See also pp. 111, 128.) This view is supported by other authors also.

*An article has just been obtained from Rodgers (1901), who shows (p. 168) that, if surra blood is fed to an animal with an abraded surface with which the blood comes in contact, infection will take place. If there is no abrasion, no infection follows.

E.? FROM DRINKING STAGNANT WATER AND EATING VEGETATION GROWN UPON LAND SUBJECT TO INUNDATION.

In discussing infection from these sources, Lingard (1899, pp. 74-75) says:

"The question of grass and water being the carriers of the contagium of surra is so intimately associated that it will be as well to consider these two factors together in their relation to the causation of the disease. The distribution of this malady seems to be entirely influenced by the physical aspect of the country. It appears to be chiefly brought about by the occurrence of floods and inundations, being far more prevalent in those parts of the country where these occur than in the higher and drier portions. It is far more common in the vicinity of the rivers and canals than in portions of the country where water is scarce. It is not usual for the natives of India to make any provision for the maintenance of their animals in the form of hay or dried grass. The usual custom is either to graze their cattle where grass is to be found or to cut it from the jungles and wastes as it is required. Toward the end of the hot season grass on the higher lands has become burnt up; at lower levels, especially at the bottoms of nalas, swamps, and ponds, where water has been lying till a much later period, an abundant supply can generally be found, and it is from these sources that it is procured.

"Similar conditions operate at intervals during the wet season, or directly the rains have ceased, especially in those parts of this country where the temperature is high at this time of the year. The lands bordering on rivers and streams, or those which are low lying, become flooded, the herbage is covered with water, which in some cases, when the land has a clayey subsoil, disappears almost entirely by gradual evaporation, and such places are favorable for the development of low forms of life, and possibly for the Trypanosoma. Animals, therefore, which daily consume grass and drink water from such localities run a risk of taking into their systems the contagium of this disease. In confirmation of these statements we may mention one example from many collected. The inhabitants of a village "Naoni” in the Ghaziabad Tahsil, of the Meerut district, visited by Veterinary Captain Pease in 1895, informed him that some 40 out of 60 camels attacked had died out of a herd of 250. The people now drive the camels away to the Bangar or higher lying grounds during the rains, and water those animals which remain in the lowlands from wells only, in order to escape the disease. They attribute the disease to stagnant water, and do not allow their camels to drink at open places until the water has stood for a considerable time and become 'pakka' (wholesome). On the other hand, Veterinary Captain G. H. Evans reported the case of a pony which contracted surra in a compound in Rangoon. The grass was obtained by its attendant from any source available, while the water supplied to the animal came from the municipal supply pipes. This was the first case of surra acquired in that city observed by the above officer during a residence of some 6 or 7 years."

Lingard's presentation of this case does not absolutely convince us that either water or grass conveys the disease. There is nothing at present known in connection with the biology of any Trypanosoma which would lead us to look seriously upon the grass and water as sources of infection with surra, notwithstanding the fact that this method of infection has been referred to by so many authors. Naturally, stagnant water will not improve the health of animals, but, on the contrary, will increase the infection with parasitic worms, and so tend to reduce the condition of the stock. Futhermore, insects

will be present in greater numbers under the conditions described, hence these localities will naturally present a greater chance for the spread of the disease. Our remarks are not to be interpreted as a denial of the possibility of infection in the way described, but simply as an expression of reserve or perhaps skepticism upon this point, pending further investigations. Our skepticism finds decided support in the remarks by Pease (1897), quoted on page 95 of this report.

F.? INGESTION OF GRAIN SOILED WITH EXCREMENT OF THE RAT AND THE BANDICOOT.

In discussing the subject Lingard (1899, p. 76) says:

"In 1891 experimental inoculation of equines proved that out of 12 animals inoculated with soiled rat's blood 4, or 33 per cent, contracted surra and died of a virulent form of the disease in an average of 7 days. The above experiments raised the question as to how rats could cause the disease in horses, for the food would rarely, if ever, be soiled with the blood of these small animals. It therefore only remained to be tried whether the excreta of rats, in whose blood the infusorian was present at the time of its collection, could cause the disease when mixed with grain. Experiments with this end in view were carried out, and one Australian horse contracted surra in 1893, the incubation period occupying some time between June and September, during which the animal received daily rat excrement mixed with its ration of corn. This was evidence that when a horse is made to ingest soiled material day by day surra may finally be contracted, but whether the disease was ever actually produced in the natural course of events by this means at that time, there was no testimony forthcoming. Inquiries were instituted in different parts of India in order to discover whether any folklore existed on the subject, and syces and keepers of horses were interrogated for a similar purpose. In June, 1895, one gentleman, with many years' experience in India, stated that it was a fixed idea in the minds of many natives in the Northwest Provinces and Oudh that if horses were allowed to eat corn soiled with rat excrement some of them would be more than likely to die within a few months.' Again, the following statement was made by an old syce: 'It is a common belief among syces that rat's dung in the corn given to horses makes them ill.' Further testimony with regard to small animals was obtained to this effect: 'Some years ago we lost a couple of goats, and the native who tended them said death was due to the rat's dung we found among the stock of gram the animals had been fed upon.'

"From the above statement it will be gathered that animals can acquire the Trypanosoma, or organism of surra, by different means. The thousands of equines which have succumbed to that disease in the Punjab alone have to shift for themselves, and under no circumstances obtain anything as fodder but the grass they can find and water from the nearest source. Therefore the question of rat excrement can be at once excluded as a factor in the causation of the disease in that class of animals. But with regard to the question of surra being communicated by the bites of a fly, we know that when once the disease is started it may be reproduced to any extent by these insects. The evidence put forward with regard to the effect of rat excrement in corn is also of great importance to the horse owner in India."

We are inclined to accept Lingard's reasoning in this case with double reserve. While it appears that rats may contract horse surra, it has not been shown that Trypanosoma are found in the excrement either of horses or of rats, nor is it clear to us that during the experi

ment mentioned, extending over three to four months, the necessary precautions were taken to exclude fly bites and other factors. If, in fact, Trypanosoma accidentally reached the feces through intestinal hemorrhage, it is not clear how they could be infectious, for rat feces dry rapidly, and drying appears to kill this parasite, as has been proved also for other species of Trypanosoma (see p. 113). Finally, even if it is assumed that the rat trypanosomiasis found was identical with the horse surra, it is at least possible that it might have been transmitted by rat fleas perhaps as easily as by the ingestion of

excrements.

SYMPTOMS OF SURRA.

GENERAL CLINICAL PICTURE.

Lingard (1893, pp. 62-64) has given the following summary of symptoms the most complete summary which has as yet been published by any author whose papers we have been able to consult:

"Before describing the symptoms of surra, it will be necessary first to divide cases of the disease under two different heads, viz: A. Those which have contracted the disease in the natural course of events; B. Those which have acquired the disease by inoculation.

"A. Symptoms of the disease as observed when contracted naturally.-The invasion of this disease is usually marked by symptoms of a trivial character; the skin feels hot, and there may be more or less fever; there is also slight loss of appetite, and the animal appears dull and stumbles during action; thus early a symptom sometimes appears, which may be the first intimation received of the animal's indisposition, and which, as a guide to diagnosis, is of great importance; it is the presence of a general or localized urticarial eruption. If the blood be examined microscopically it may be found to present a normal appearance, but in the majority of cases a few small, rapidly moving organisms will be observed, giving to the blood, as it passes amongst the corpuscles, a peculiar vibrating movement, which if once observed will not readily be forgotten. If the hematozoon has not been discovered in the blood for some days, the before mentioned may be the only symptoms noticeable, and as a rule, when treated with febrifuges, the horse quickly improves in health and the appetite returns. This condition does not last for more than a few days, when the animal is again observed to present a dull and dejected appearance, and on examination wellmarked symptoms are found; the skin is hot, the temperature more or less elevated, 38.7° to 40° C.; the pulse full and frequent, 56 to 64 beats per minute; the visible mucous membranes may appear clean, but the conjunctival membranes, especially those covering the membrana nictitans, are usually the seat of dark-red patches of ecchymosis, varying in size in different animals. There is more or less thirst and slight loss of appetite, the animal eating its corn and green grass, whilst leaving all or a portion of the dried grass with which it has been supplied. At the same time there are slight catarrhal symptoms present, including lachrymation and a little mucous discharge from the nostrils. Occasionally at this period of the disease the submaxillary glands may be found enlarged and perhaps somewhat tender on manipulation. One symptom is markedly absent, namely, the presence of rigors, or the objective signs of chilliness. In addition it will be noted that there is some swelling and edema of the extremities, generally between the fetlock and the hock, which pits but is not painful on pressure, and in the cases of horses there may be present also at this stage of the disease some swelling of the sheath. When the fever

and concomitant symptoms have declared themselves during a short period, one thing becomes especially noticeable in every animal attacked, namely, the rapidity with which it loses flesh. If the blood has been examined microscopically during the second period of fever, at first a few hematozoa will have been observed in it, which day by day increase in number and reach a maximum, where they remain for a varying period, or at once suddenly or gradually disappear during the period of apyrexia. After the fever and the accompanying symptoms have for the second time been present for some days, the period varying from one to six, the animal is found to have lost the dull, dejected appearance and to look bright. The elevated temperature has fallen and, in some cases, has attained normal or even subnormal limits. The visible mucous membranes are clean and the conjunctival petechia begin to fade; the pulse, however, will be found to be weak and thready in character, but the appetite excellent, and, in fact, if it were not for the loss of flesh and slight edema of the extremities, there would be little to show that the animal was ailing. But unfortunately this condition does not continue for any length of time, for again the temperature is elevated; in the course of a few hours the thermometer registers a still higher degree, the animal is dull and dejected, and by the following day the visible mucous membranes present a yellow tinge; large ecchymoses, dark in color, appear on the conjunctival membranes; the action of the heart is irritable, the pulse full and quick, or at times intermittent, and regurgitation may be observed in the jugulars; the breathing is quickened and the individual respirations shallow. On watching an animal in this condition it may be noticed that it takes seven to eight very short inspirations, and these are followed by a much more prolonged and sonorous one; at the same time the breathing is more abdominal than thoracic in character. On examination of the extremities it will be found that the swelling and edema have increased considerably, and that on the undersurface of the abdomen, where it was previously confined to the sheath, it has now commenced to spread forward along the subcutaneous tissue between the skin and the muscles. During the whole of this time the appetite will have varied little, and the evacuations will be only slightly, if at all, altered in character. In the blood a repetition of the previous events takes place, the hematozoa make their appearance and run up to a maximum, and again suddenly or gradually disappear according to the length of the fever period. These periods alternating with and without fever may go on for a considerable time. The progress of the disease is variable, and greatly depends upon the condition of the animal attacked, the weak ones succumbing very rapidly; but each bout of the fever brings with it, as a rule, an increase in the severity of the symptoms. There is augmented yellowness of the membranes, fresh crops of petechiæ on the conjunctiva, a collection of gelatinous material at the inner canthi, which at times becomes red in color from an admixture of blood, and which on microscopical examination is found to contain a varying number of the surra hematozoa; increased swelling and edema of the extremities and abdomen, which now extends between the fore limbs and up the chest. During this time the wasting has been steadily progressive, especially the muscles of the back and those surrounding the hip joint and the glutei. "Toward the termination of the disease, it will be noticed that an animal is disinclined to move, and when made to do so there will be manifest loss of power over the hind quarters, somewhat simulating a slight partial paralysis, and the hind quarters of the animal reel from side to side. In connection with this it may be noted that there is frequently present paralysis of the sphincter ani and a dilated condition of the anus. These symptoms taken together point to some interference with the normal functions of the spinal cord in the lower dorsal and lumbar regions, and are probably due to pressure caused by an exudation within the spinal membranes. In many cases shortly before death the heart's action becomes exceedingly violent, shaking the whole frame at each beat, so that the sound can be heard at some distance from the animal. In some of these cases the animal may suddenly drop dead; in others