Societies and Academies
In: Nature, Jg. 85 (1910-12-22), Heft 2147, S. 259-262
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LONDON. Royal Society, December 8.—Mr. A. B. Kempe, treasurer and vice-president, in the chair.—Sir W. de W. Abney: Colour-blindness and the trichromatic theory of colour-vision. Part ii.: Incomplete red or green blindness. In this paper the author continues the subject of the trichromatic theory of colour-vision and colour-blindness. In part i. he treated of complete colour-blindness, and in this paper, part ii., he treats of incomplete colour-blindness. He shows how the amount of incompleteness can be accurately determined from the luminosity curve of a colour-blind person both red and green blind. He also shows that the amount of incompleteness can be determined from observations made by the red- or green-blind at any part of the spectrum if someone with normal vision makes observations at the same place, using unchanged white light for the comparison. Incidentally, he shows that the three sensation components of the different colours of the spectrum, as determined by himself, are verified by the results, and that the trichromatic theory fully accounts for all cases of incomplete colour-blindness which he has measured.—Lord Rayleigh: The sensibility of the eye to variations of wave-length in the yellow region of the spectrum.—Sir D. Bruce and others: Trypanosome diseases of domestic animals in Uganda. IV.: Trypanosoma uniforme, sp. nov.—Sir D. Bruce and others: Trypanosome diseases of domestic animals in Uganda. V.: Trypanosoma nanum(Laveran).—Major Ronald Ross and D. Thomson: Some enumerative studies on malarial fever. The object of these researches was to make a minute coordinated study of cases of malarial infection occurring in the Tropical Ward of the Royal Southern Hospital at Liverpool. The first care of the authors was to elaborate a method by which the number of parasites could be correctly counted, and the one which they adopted was to make a measured quantity of blood into a dehæmoglobinised thick-film, and then to count the organisms contained in it. Almost daily estimates of the number of parasites, with frequent estimates of the leucocytes, the hæmoglobin, and the excreted urobilin, were made since the beginning of this year in twenty-four cases of Plasmodium falciparum, eight cases of P. vivax, and one case of P. malariaeand P. falciparum. Correlation with minor deviations was found between the number of asexual parasites present and the degree of fever. If the asexual forms did not number more than several hundreds per cm. they were not numerous enough in these cases to produce fever. The asexual forms do not disappear between relapses, as usually thought, but tend to diminish. It is roughly estimated from these cases that quinine reduces the asexual forms by 50 to 80 per cent.—G. C. E. Simpson: Hæmoglobin metabolism in malarial fever. (Preliminary note.) In the pyrexia of malaria there is a marked fall in the hæmoglobin of the blood, and further investigation of this question was undertaken in the hope that it might throw light on the relationship of malaria and blackwater fever. In benign tertian malaria a slightly increased output of urinary urobilin occurs, in malignant tertian malaria a greater increase, and in the malignant form mrked urobilinuria was sometimes found.—Major Ronald Ross and D. Thomson: A case of sleeping sickness studied by precise enumerative methods; further observations. Conclusions.—(1) The increase of trypanosomes is due to their active multiplication, depending on the following conditions:—(a) the liberation of a reproductive stimulant from the dead trypanosomes of the previous fall; (b) the small number of leucocytes, especially mononuclears; (c) the habituation of the trypanosomes to their antibodies; (d) the absence or diminution of antibodies. (2) The decrease of trypanosomes is due to their rapid death, and to a cessation of multiplication depending on the following conditions:—(a) the large increase of leucocytes, especially of mononuclears; (b) the formation of antibodies in the serum. (3) The trypanosomes remaining between the rises are resistent forms. (4) Extracts of dead cells would appear to stimulate the corresponding live cells to multiply or divide.—Dr. H. B. Fantham and J. G. Thomson: Enumerative studies on Trypanosoma gambienseand Trypanosoma rhodesiensein rats, guinea-pigs, and rabbits; periodic variations disclosed, (1) The strains of trypanosomes used in these investigations were:—(a) T. gambiense, old laboratory strain; (b) T. rhodesiense(Stephens and Fantham), from a patient suffering from sleeping sickness in Rhodesia. (2) Rats, guinea-pigs, and rabbits were inoculated with a definite number of trypanosomes, and daily counts were made of the parasites in the peripheral blood of the animals. (3) Periodic variation was found in all these animals comparal to that discovered by R. Ross and D. Thomson in the olood of the sleeping sickness patient. (4) Rats inoculated with each strain showed either a periodic increase or a continuous rise in the numbers of parasites. (5) The average life of rats inoculated with T. rhodesiensewas 11.3 days, with T. gambiense13.8 days. (6) The average incubation period in rats in the case of T. rhodesiensewas 2.9 days, in T. gambiense4.4 days. The average weights of the animals and the average number of parasites inoculated were approximately the same in the two strains. (7) In rats infected with T. rhodesiensethe period between the crests of the graph was 3 to 4 days, while in T. gambiensethis period was 4 to 6 days. (8) In guinea-pigs the trypanosomiasis tended to run a chronic course, but the life of animals infected with T. rhodesiensewas snorter. The period between the crests of the graph in both strains was longer than in rats, namely, 5 to 8 days. (9) Rabbits inoculated with T. rhodesiensealso exhibit periodic variation. (10) The periodicity is explained by (a) variations in resistance on the part of the host, accompanied by (b) the formation of latent bodies by the trypanosomes in the internal organs of the host during fall in numbers of the parasites in the peripheral blood.—Dr. H. B. Fantham: The life-history of Trypanosoma gambienseand Trypanosoma rhodesienseas seen in rats and guinea-pigs, (1) The researches were undertaken to investigate the parasitological aspect of the numerical cyclical development found by R. Ross and D. Thomson in the trypanosome of a patient suffering from sleeping sickness contracted in Rhodesia. Rats and guinea-pigs inoculated with T. rhodesienseand with T. gambiensewere killed at various stages of infection and their internal organs examined, controls being used. (2) The formation of a non-flagellate, latent or rounded body from a trypanosome was observed in life, much of the cytoplasm and the flagellum of the flagellate being cast off. (3) Non-flagellate bodies were seen to grow into flagellate trypanosomes when placed in fresh, warm, uninfected blood. (4) The latent or non-flagellate stages are formed at or near the time when the trypanosomes are most numerous in the peripheral blood. (5) The latent bodies are relatively numerous in the internal organs when the flagellates are few in the peripheral blood of the host. (6) The formation of latent bodies takes place especially in the lungs. The latent bodies collect in the spleen and bone-marrow, as stated by Salvin-Moore and Breinl. (7) Latent bodies from the spleen of an infected rat inocu lated into another rat produced trypanosomiasis. (8) The latent bodies are the post-flagellate stages of one generation of trypanosomes and the pre-flagellate stages of the succeeding generation. (9) There is a life-cycle of T. gambienseand of T. rhodesiensein vertebrate hosts. (Compare Crithidia and Herpetomonas in invertebrates.) (10) The occurrence of latent bodies explains the recurrence of trypanosomiasis in hosts when it has apparently died out. (11) Mutual action and reaction of the host and the parasite lead to the formation of rounded bodies, which are relatively resistant. (12) Some flagellate trypanosomes do not form latent bodies, but degenerate. Some latent bodies die, and do not flagellate.—Major R. Ross and J. G. Thomson: Experiments on the treatment of animals infected with trypanosomes by means of atoxyl, vaccines, cold, X-rays, and leucocytic extract; enumerative methods employed. In all the animals used in these experiments regular daily counts were made of the parasites in the peripheral blood by means of thick-film method, (1) Small repeated doses of atoxyl prolonged the lives of rats infected with the Rhodesian strain of trypanosomes, but failed to have any trypanocidal action, as was demonstrated by the fact that the parasites increased rapidly and showed very active division. (2) We venture to suggest that small doses of atoxyl actually stimulated the trypanosomes of this strain to divide, and that the drug is also a tonic to the body cells of the host. (3) Large doses of atoxyl are trypanocidal, but the parasites form resistant bodies, and cure is only temporary. The dose required to approach as near lethal as possible, and even then a cure was not obtained in the Rhodesian strain. (4) Vaccine treatment gave indefinite results, and insufficient experiments prevent definite conclusions being formed. The life of one rat seemed to be prolonged when the vaccine was administered in doses of 10,000,000 trypanosomes, with an interval between the doses. We suggest that the time of administration, the amount given, and the interval between the doses are all of importance, and further work is being carried out. (5) Animals suffering from trypanosomiasis had the incubation period delayed and their lives prolonged in the cold. (6) X-rays had no trypanocidal action, but the life of the animal may have been prolonged. (7) Leucocytic extract gave indefinite results.—A. Campbell and D. W. Dye: Sound vibrations of very high frequency produced by electric sparks.
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Societies and Academies
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Zeitschrift: | Nature, Jg. 85 (1910-12-22), Heft 2147, S. 259-262 |
Veröffentlichung: | 1910 |
Medientyp: | serialPeriodical |
ISSN: | 0028-0836 (print) ; 1476-4687 (print) |
DOI: | 10.1038/085259a0 |
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