26o 



NATURE 



[December 22, 1910 



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 Rayleigrh : The sensibility of 

 the eye to variations of wave-length in the yellow region 

 of the spectrum. — Sir D. Bruce and others : Trypano- 

 some 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 dehaemoglobinised thick-film, and then to 

 count the organisms contained in it. Almost daily esti- 

 mates of the number of parasites, with frequent estimates 

 of the leucocytes, the haemoglobin, 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. malariae and P. falci- 

 parum. 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 : Haemo- 

 globin metabolism in malarial fever. (Preliminary note.) 

 In the pyrexia of malaria there is a marked fall in the 

 haemoglobin 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 uro- 

 bilinuria was sometimes found. — Major Ronald Ross and 

 D. Thomson : A case of sleeping sickness studied by 

 precise enumerative methods ; further observations. Con- 

 clusions. — (i) The increase of trypanosomes is due to their 

 active multiplication, de{>ending on the following condi- 

 tions : — (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 leuco- 

 cytes, 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 

 gambiense and Trypanosoma rhodesiense in rats, guinea- 

 pigs, and rabbits ; periodic variations disclosed, (i) 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 com- 

 paral .*z 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 in- 

 crease or a continuous rise in the numbers of parasites. 

 (5) The average life of rats inoculated with T. rhodesiense 

 was 11-3 days, with T. gambiense 13-8 days. (6) The 

 average incubation period in rats in the case of T. 

 rhodesiense was 2-9 days, in T. gambiense 4-4 days. The 

 average weights of the animals and the average number 

 of parasites inoculated were approximately the same in the 

 NO. 2147, VOL. 85I 



two strains. (7) In rats infected with T. rhodesiense the 

 period between the crests of the graph was 3 to 4 days, 

 while in T. gambiense this 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. rhodesiense 

 was shorter. 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. rhodesiense also 

 exhibit periodic variation. (10) The periodicity is ex- 

 plained 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 

 gambiense and Trypanosoma rhodesiense as seen in rats 

 and guinea-pigs, (i) 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 sick- 

 ness contracted in Rhodesia. Rats and guinea-pigs 

 inoculated with T. rhodesiense and with T. gambiense 

 were 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 cyto- 

 plasm and the fiagellum 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 genera- 

 tion of trypanosomes and the pre-flagellate stages of the 

 succeeding generation. (9) There is a life-cycle of T. 

 gambiense and of T. rhodesiense in vertebrate hosts. 

 (Compare Crithidia and Herpetomonas in invertebrates.) 

 (10) The occurrence of latent bodies explains the recur- 

 rence 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, (i) Small 

 repeated doses of atoxyl prolonged the lives of rats in- 

 fected with the Rhodesian strain of trypanosomes, but 

 failed to have any trypanocidal action, as was demon- 

 strated 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 trj'pano- 

 somes 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 reauired I 

 to approach as near lethal as possible, and even then a | 

 cure was not obtained in the Rhodesian strain. (4^ Vac- i 

 cine treatment gave indefinite results, and insufficient \ 

 experiments prevent definite conclusions being formed, j 

 The life of one rat ceemed to be prolonged when the 

 vaccine was administered in doses of 10,000,000 trypano- i 

 somes, with an interval between the doses. We, 

 suggest that the time of administration, the amount given, j 

 and the interval between the doses are all of importance, 

 and further work is being carried out. (5) Animals suffer- ; 

 ing 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 in-' 

 definite results. — A. Campbell and D. W. Dye: Sound; 

 vibrations of very high frequency produced by electric sparks. , 



