52 



NATURE 



[September 9, 19 15 



magnetism, electric potential, and earth tempera- 

 ture. From the Astronomische Nachrichten (No. 481 1) 

 we learn that the 6-in. Repsoid heliometer of the 

 Leipsic Observatory was employed by Von Naumann, 

 assisted by Frl. Kuschel, for measures of the position 

 angles of the cusps at chronographically recorded in- 

 stants through the greatest phase ; 150 measures were 

 obtained in about fifty-two minutes. The following 

 corrections to the ephemerides were obtained : — 



da= + ii-4''±o-i2", d8=-3-6"±o-o8". 



The solar co-ordinates were taken from the Berliner 

 Jahrbuch ; the moon 's position was derived from the 

 Nautical Almanac. 



Colour Index and Distance of Stars. — Mr. P. J. 

 van Rhijn, who has been working at the Mount 

 Wilson Observatory, has presented an important 

 memoir to the University of Groningen as thesis for 

 doctorate dealing with the change of colour with dis- 

 tance and apparent magnitude, including a new deter- 

 mination of the mean parallaxes of the stars of given 

 magnitude and proper motion. The stellar data em- 

 ployed in the paper are : — (i) Colour or photographic 

 and visual magnitude ; (2) sjpectral type ; (3) distance. 

 Colour and spectral type have been taken from the 

 Yerkes actinometry. Distance has been determined 

 according to Kapteyn's method of deriving mean 

 parallaxes from proper motions and magnitudes, and 

 then calculating the mean distances on the hypothesis 

 that the logarithms of the ratio of true parallax to the 

 most probable parallax of stars having the same magni- 

 tude and proper motion are distributed according to the 

 law of errors. The data permitted these values to be 

 satisfactorily obtained for the helium and second-type 

 stars, but for the A-type paucity of parallaxes neces- 

 sitated different treatment. As would be expected, 

 Mr. van Rhijn has obtained results in good accord 

 with those of Kapteyn, whilst the exclusion of stars 

 with large angular motions is shown to be responsible 

 for the opposed conclusions reached by Dr. Campbell. 



Having obtained numerical expressions for the mean 

 distances of the stars, Mr. van Rhijn proceeds to deal 

 with the colour index. This has been taken as the 

 summation of the effect of distance and apparent 

 magnitude, the effect of absolute magnitude for various 

 reasons having been given a zero coefificient. Out of 

 the laborious calculations involved in the solution of 

 the colour index equations the following results have 

 emerged. The faint stars, and also the distant stars, 

 are, ceteris paribus, redder than the bright stars and 

 the near stars respectively. The increase of the colour 

 index found being +o-025m. ±0-004 P^r cent, per unit 

 of visual magnitude, and +o-ooo 15m. ±0-00003 pei" 

 cent, per unit of distance (parsec). 



It is possible that the B stars and also the early A 

 stars are immune from the distance effect. If that 

 were so, the coefficient for the remaining spectral 

 types would be increased to a value 6-5 times 

 its probable error. The effect may be due either to 

 an absorption of light in interstellar space or to an 

 influence of absolute magnitude on colour. 



M^ 



RECENT STUDIES OF CERTAIN TROPICAL 

 DISEASES. 

 "ANY features of much interest are presented in 

 the current number of the Annals of Tropical 

 Medicine and Parasitology (vol. ix.. No. 2, June 30). 

 The opening article, by Dr. Breinl, deals with the 

 ulcerative disease known as Gangosa, or Rhinopharyn- 

 gitis mutilans, as observed by him in New Guinea. 

 The causal agent of the disease is considered to be 

 NO. 2393, VOL. 96] 



a new species of Cryptococcus (C. mutilans), of which 

 illustrations are given in a coloured plate. The 

 ravages due to Gangosa are forcibly demonstrated 

 by three plates of photographs of different cases. The 

 second paper, by Dr. H. Priestley, deals with Theileria 

 tachyglossi, a protozoan parasite found in the blood 

 and internal organs of an Echidna, Tachyglossus 

 aculeatus, from the neighbourhood of Townsville, 

 Queensland. This article is of interest as being the 

 first record of the organism from marsupials. The 

 parasite closely resembles Theileria parva of African 

 East Coast fever in cattle. A coloured plate depicts 

 the forms of the parasite observed. 



The investigation into the causes of the prevalence 

 of typhoid or enteric fever in Kingston, Jamaica, is 

 ably set forth by Dr. H. H. Scott in the third paper. 

 The mode of infection of food and milk. supplies and 

 the means of detection of unrecognised carriers of the 

 typhoid bacillus are described, and should be of ser- 

 vice to workers both at home and in the tropics. 

 Water supplies and sewage disposal are also con- 

 sidered. The post-mortem findings and the results of 

 cultivation of the bile from 120 consecutive autopsies 

 are given in tabular form. Eighty more cultivations 

 have since been made. From the total of 200 there 

 have been six cases from which the bacillus has been 

 isolated, apart from those subjects who showed post- 

 mortem signs of enteric fever. There are also 

 numerous charts showing the seasonal prevalence of 

 the disease in Kingston. 



Another paper by Dr. Breinl deals with the occur- 

 rence of various diseases prevalent on the coastal belt 

 of British New Guinea. Eight plates of photographs 

 illustrate the article. Certain diseases, such as 

 malaria, are already known there, but less work has 

 been done on others. Leprosy, filariasis, various 

 curious fevers, juxta-articular nodules, yaws, tropical 

 ulcers, contracting sores, destructive interdigital 

 ulcers, and gangosa have been found among the 

 natives. Only the regional distribution of the mala- 

 dies has so far been attempted in any detail. New 

 Guinea should provide a rich field for further research 

 in tropical medicine. 



The concluding paper is by Dr. Fantham, and deals 

 with insect flagellates and the evolution of disease, 

 with a plea for the recognition of the importance of 

 comparative methods in the study of protozoology. 

 The leishmaniases are used in illustration, and their 

 origin from insect flagellates which are able to adapt 

 thernselves to life in vertebrates is discussed. The 

 significance of the herpetomonad flagellate stage of 

 Leishmania, and the existence of such a stage in man, 

 at any rate in L. tropica, is indicated. The discovery 

 of natural herpetomonads in mice by Dutton and Todd 

 and by Fantham and Porter is recalled, as well as the 

 occurrence of herpetomonads pathogenic to plants 

 (Euphorbia spp.). The recent striking experiments 

 of Laveran and Franchini on the introduction of 

 herpetomonads into mammals, and of Fantham and 

 Porter on the introduction of these flagellates into 

 marnmals, reptiles, amphibia, and fishes are sum- 

 rnarised. In these experiments the evolution of the 

 disease, that is, "leishmaniasis in the making," is 

 revealed. 



THE T ALGA I SKULL. 



"pERHAPS the most remarkable incident of the 

 -»■ meeting of the British Association in Australia 

 last year was the demonstration given by Profs. 

 Edgeworth David and Wilson to Section H 

 in Sydney of a completely mineralised skull found 

 in the neighbourhood of Talgai in the Darling Downs, 

 Queensland. When war broke out and Prof. Wilson 



