unsuccessful, although they repeatedly introduced into one rat blood rich in parasites and nourished one rat chiefly by this material. They placed together an infected tame rat and a noninfected wild rat, and state that after a hot combat the tame one was killed by the wild rat and eaten with much pleasure. Parasites appeared in his blood after ten days. They did not regard this as a case of infection necessarily by the digestive tract, as the parasites may have entered by the numerous bites and wounds, nor do we regard it as such; but we think we have in our experiments removed the likelihood of entrance through wounds and have established the existence of infection through the digestive tract alone.

5. Transmission by fleas.-Rabinowitsch and Kempner, with a view to finding the natural mode of transmission, placed together an infected white rat with a healthy white rat. The latter became infected in eleven days. They repeated the experiment and found parasites in the blood of another rat after fifteen days. A gray rat showed parasites in his blood after fifteen days' confinement with two infected animals. The three rats which became infected had many fleas on them. Examination of a great number of teased preparations of the fleas did not reveal any of the trypanosomes in them. They then mashed up fleas collected from infected rats and injected this material into the peritoneal cavity of nine white rats. Five became infected. Likewise four rats were injected intraperitoneally with mashed-up lice, I but no infection followed. The next experiment was to determine whether the bites of fleas were infective. Twenty fleas were collected from infected rats and placed on one healthy white rat, which after three weeks time was found to be infected with trypanosomes. They say that from this one positive experiment they conclude that fleas can carry trypanosomes, and in the absence of proof of another way of conveyance they are of the opinion that fleas are the ordinary medium of infection.

Jourgens states that his experiments were not then complete, but that he had kept infected rats and healthy rats together in the same cage without infection taking place, although the animals were strongly beset with fleas, while a later inoculation of the sound aniImals proved them to be susceptible.

6. Trypanosomes in lice.-Laveran and Mesnil found trypanosomes in the stomachs of lice which infested infected rats, but do not report a conveyance of the disease by lice bites.

7. Trypanosomes in Stegomyia fasciata.—We may be pardoned for mentioning a subject which is entirely outside of rat trypanosomes— but it may have some future bearing on the disease-to state that within a year Durham (10) has reported finding trypanosomes in a mosquito, thus adding one more to the rapidly growing list of diseases through which this little creature threatens the public health. Durham's report is inserted.

A small bat (Phyllostoma) which could not be examined at once was placed in a gauze cage, and with it a specimen of Stegomyia fasciata. The next day the bat

was dead and the mosquito full of fresh blood. This blood contained abundant trypanosomes, whose shape is quite different from the usual ones found in rats, Nagana, etc. * * * Although flagellates, coccidia-like bodies, etc., often were found from time to time in the 80 mosquitoes which were dissected, this was the only time that trypanosomes were found.

THE PARASITES OUTSIDE THE BODY.

We must confirm the reports of Wasielewski and Senn, and of Rabinowitsch and Kempner, that if hanging drops are made of blood containing parasites in different stages of division a careful watching of the specimen will not witness the completion of the division process, whether the specimens be kept at room temperature or in the ice box or in the incubator.

Jurgens found quite the contrary. He made three hanging drops of the same blood with the same platinum loop. No. 1 was placed at 37° C. No. 2 was kept at room temperature. No. 3 was immediately dried, fixed, and stained, and examination showed it to contain parasites preparing to divide. On the next day Nos. 1 and 2 were dried, fixed, and stained. The stained specimen of No. 2 always showed the same conditions as No. 3; but in the stained specimen of No. 1 there were rosettes and division forms, none of which was seen in No. 3. Therefore, he concludes that it is possible for certain stages of the parasite under certain conditions to increase outside the body. It will require further investigation to determine whether the parasite exists in the flea's body in the forms known to us as young forms, division forms, and adult parasites, or whether there is still another form which has not yet been described. The fact of not being able to find in infective fleas any form resembling a trypanosome has a close parallel in what occurred in one of our rats. A white rat in whose blood we saw many parasites in agglutination for several days suddenly showed an absence of parasites from the blood. We immediately performed an autopsy and made a careful search of the lungs, liver, spleen, kidneys, heart, brain, and bone marrow for parasites, but could find none. We were struck by the amount of granular débris in the liver and kidneys, but could not see any trypanosomes in them.

An emulsion was made of the kidneys and injected into the peritoneal cavity of a young rat. The liver was treated in the same manner and injected into two young rats. On the ninth day all three rats had parasites in their blood and a few days later developed heavy infections. While some unknown form of the parasite may have been present, it is of course possible that well-known forms of the trypanosomes were in the kidneys and liver and escaped notice. Jurgens produced infection with 0.000005 c. c. of blood. If this amount of blood be added to 1 or 2 c. c. of salt solution, the dilution of the parasites would be so great that they might readily be missed in hanging-drop preparations.

The possibility of the existence of some very minute form of the

parasite was perhaps excluded by our filtration experiments. Trypanosome blood was diluted with fifteen parts of physiological salt solution and subjected to a porcelain filter under the influence of a vacuum. The filtrate was found to be noninfective to rats.

In blood kept in the ice chest for eighty-one days we found living trypanosomes. Their motion was of a trembling, vibrating character. Very few crossed the field. Many were arranged in rosettes. In the stained preparations we found parasites in which the positions of the centrosome and nucleus were reversed, the centrosome being anterior to the nucleus. In many of the trypanosomes there was granular degeneration, and there was also much free granular débris, which probably represented the remains of degenerated parasites. At room temperature and at 37° C. the parasites are short-lived. The different investigators found them capable of producing an infection of rats after being kept in the incubator and at room temperature from four to seven days. The parasites when kept at 12° to 16° C. in sterile pipettes can maintain their vitality very much longer than under any other condition.

Laveran and Mesnil kept parasites alive in defibrinated blood or in equal parts of defibrinated blood and physiological salt solution for forty-seven days in the ice box. At the end of this time the blood was injected into rats and produced a blood infection in nine days. In blood kept under the same conditions for fifty-one days they saw no parasites by microscopic examination, but it was infective for rats. Jurgens found only a few parasites in blood kept in the ice chest for fifty-three days, but rats injected with it showed parasites in their tail blood after seven days.

Bacteria have a very detrimental effect on the life of the parasites outside the body. In hanging drops of trypanosome blood which has become infected with bacteria the parasites rapidly die.

drawn for keeping in the ice box must be kept under sterile conditions. Trypanosomes are killed after an exposure of a few minutes at 55° C. Wasielewski and Senn found living trypanosomes in the bloody urine of a rat. Rabinowitsch and Kempner were never able to find the parasites in the feces or urine.

THE TRYPANOSOME OF THE HAMSTER.

This animal harbors a parasite which has been studied by Rabinowitsch and Kempner. They find that it resembles the rat trypanosome in that it can hardly be differentiated from it morphologically and has the same process of development. On the other hand, they could not convey it to rats, and some of the rats which were refractory to hamster trypanosomes later proved susceptible to rat trypanosomes. These facts, taken together with the fact that they could not convey rat trypanosomes to the hamster, led them to conclude that the hamster trypanosome and the rat parasite represent two different physiological varieties, which morphologically are almost inseparable.

TRYPANOSOMIASIS IN MAN.

Trypanosomiasis as a disease of man has not yet become acclimatized in the United States. At least no cases have been reported in this country. There have appeared in the foreign journals within the past year, however, eleven authentic instances of infection with trypanosomes.

A case of trypanosomiasis in a European, by Dutton (11) and Forde (12). The patient was a European, 42 years of age, master of a government steamer on the Gambia River, in West Africa.

On May 10, 1901, the patient was admitted into the hospital at Bathurst, West Africa, suffering from what was regarded as malarial fever. Examination of his blood did not show malarial parasites, but | there were seen extremely active bodies which were regarded as filaria. Three weeks later the patient was invalided to Liverpool, but returned in December, 1901, to Bathurst, where Dr. Dutton, of the Liverpool School of Tropical Medicine, examined the patient's blood and found the same parasite which Forde had probably seen seven months previously and which he at once recognized as a trypanosome.

The symptoms were an irregularly intermittent fever, a very marked erythema multiforme of the trunk and limbs, an oedematous condition of the face beneath the eyes and of the ankles, an acceleration of respiration and pulse rates, debility and loss of flesh, and enlarged spleen. The symptoms persisted throughout the eight months during which he was under observation and showed no reaction to treatment further than a slight abeyance under Fowler's solution.

Dutton found, while making examinations of fresh blood during the month of December, 1901, an average of one and one-half trypanosomes to each cover slip preparation. One preparation showed as many as 15 parasites. This case continued in its chronic course until the last week of life, during which week the disease assumed an acute type and the patient died January 1, 1903.

Dutton suggests the name Trypanosoma gambiense in case that further study shows it to be a new species.

A second case of trypanosomiasis in a European, by Manson (13).— The patient was the wife of a missionary on the Upper Kongo, where she had lived for a year. On account of sickness she returned to

London.

Dr. Manson, of the London School of Tropical Medicine, recognizing the same group of symptoms which the patient of Dutton and Forde presented, made systematic, careful examinations of her blood daily for two weeks. During the two weeks no trypanosomes were found, but at the end of this time the parasites were readily seen in the peripheral circulation.

Trypanosomes in the blood of a West Africa native, by Dutton (14).—Three trypanosomes were found in a single smear from the

blood of a child 3 years of age, a native of Gambia. The child showed no symptoms of disease.

Eight additional cases of human trypanosomiasis. In the British Medical Journal for February 7, 1903, there is a "preliminary account of the investigations of the Liverpool expedition to Senegambia," by Dutton, Annett, and Todd. They found trypanosomes in the blood of a white trader who had been twenty years in Gambia. The highest number found in a fresh preparation was seven. The patient had lost 45 pounds within the past year, complained of weakness and breathlessness, and had slight fever at times. The spleen was enlarged and there was pitting of the ankles. Four other cases of infection of natives were found.

Three more cases of human trypanosomiasis are reported in the British Medical Journal for March 28, 1903, by Dr. Patrick Manson. They came from the European community on the Kongo, as did also Dr. Manson's first case. A blotchy erythema and attacks of fever

characterized these cases.

The finding of trypanosomes in man, associated with a well-defined group of signs and symptoms, is no small contribution to the disentanglement of the diseases of the Tropics. These cases will lead to the recognition of others, perhaps, in the tropical parts of our own continent or of Asia. The disease has been found in West Africa, and with this new fact in parasitology before us its geographical distribution may be found to have a much wider range. On account of the interest which surra claims in the Philippines and on account of the recognition within the past year of trypanosomes in man, and since the process of development and conveyance of these blood parasites have heretofore been little investigated in this country, we have undertaken this study.

We wish to call attention to the autoagglutination, transmission by feeding, transmission by intrastomachal injection, and to the staining. I am glad to thank the director of the laboratory, Dr. M. J. Rosenau, for his interest in outlining the work.

I am indebted to Dr. John F. Anderson, the assistant director, for valuable suggestions, especially in the staining of the parasites.

I also desire to express my thanks to Dr. H. B. Parker for making the microphotographs.

REFERENCES.

1. Salmon, D. E., and Stiles, Ch. Wardell: Emergency report on surra. Bureau of Animal Industry, Bulletin No. 42. Washington, 1902.

(This bulletin contains a complete bibliography of surra and allied trypanosomatic diseases by Albert Hassall.)

2. Crookshank: Flagellated protozoa in the blood of diseased and apparently healthy animals. Journ. Royal Microscop. Soc., November, 1886.

3. Rabinowitsch, Lydia, and Kempner, Walter: Beitrag zur Kenntniss der Blutparasiten, Speciele der Rattentrypanosomen. Zeitschrift für Hygiene, Vol. XXX, 1899.