November 8, 1 900] 



NA TURE 



33 



Necessarily there has been some dififerences of 

 opinion, and what has been found true in one place has 

 been denied elsewhere. This is not remarkable if one 

 considers how much mosquito life and habits are influ- 

 enced by meteorological factors, and these obviously 

 differ greatly in different latitudes and at different alti- 

 tudes. On certain essential points, however, all observers 

 are agreed : malaria is caused by three (possibly four) 

 species of the Hasrnamoebidae, and these are indisputably 

 conveyed from man to man by mosquitoes of genus 

 Anopheles. 



Another important point has been noted in West 

 Africa by Stephens and Christophers and by Koch in 

 Java and elsewhere. Native children of one to three 

 years old are peculiarly the victims of malaria para- 

 sites, and as they grow older the invasion by parasites 

 becomes less and less. These facts have been taken to 

 prove what has long been asserted, viz., that prolonged 

 residence in a malarial country produces a relative 

 amount of immunity. 



Koch used the presence or absence of parasites in the 

 blood of young children as a criterion of the question as 

 to whether malaria was endemic or merely imported. It 

 further shows how great a danger to white men is living 

 in close proximity to native habitations. This has been 

 insisted on in West Africa, much to the indignation of 

 the educated blacks. 



Incidentally, additions to our knowledge of the fauna 

 of West Africa have been made by these expeditions. 

 Mr. Ernest Austen, of the Zoological Department, British 

 Museum, accompanied the first expedition to Sierra 

 Leone, and a report on his work there has been recently 

 published by the authorities of the museum. 



Fifteen hundred specimens of insects were obtained, 



chiefly of the Lepidoptera, Diptera and Neuroptera, 



though four other orders were represented in the collection. 



In his report Mr. Austen describes a variety of Tsetse 



fly {Glossina longipalpis), and a Muscid (probably new) 



known locally as the "Tumba" fly. The latter deposits 



its egg under the skin of man and other animals, and 



'- when the larva is hatched a boil of a peculiarly 



painful character is produced. The departure of Mr. 



\ Austen, immediately on his return from Sierra Leone, to 



• South Africa with the City Imperial Volunteers has 



prevented us as yet of obtaining the full fruits of his 



work, which, now that he has safely returned, we shall 



eagerly look for. 



The best methods of malaria prophylaxis have been 

 much discussed. The original views of Major Ross and 

 the first Liverpool expedition, in the light of wider and 

 more recent knowledge, seem somewhat too sanguine. 

 The destruction and extermination of mosquitoes by 

 drainage and the use of culicicides, as suggested in their 

 report, is now regarded as impracticable in some dis- 

 tricts, although in many places these methods, in con- 

 junction with the intelligent use of mosquito-curtains and 

 quinine, could not fail to bring about a marked improve- 

 ment. 



On the whole, however, we must rely, as Dr. Manson 

 has insisted, on the prolonged treatment of patients with 

 quinine and during the time they have parasites in their 

 blood on their rigorous isolation and protection from 

 mosquitoes. 



Paradoxical as it may seem, we must first aim at pre- 

 serving mosquitoes from infection and so limit the 

 chances of the dissemination of the parasites as far as 

 possible. 



It cannot be too strongly emphasised that in a 

 malarious country where Anopheles are present a case of 

 fever is infectious. 



The value of the proper use of mosquito netting is 

 strikingly shown by the following experiments. In March 

 last Dr. Manson, speaking at the Colonial Institute, 

 announced that the Colonial Office, in conjunction with 



NO. 1619. VOL. 63] 



the London School of Tropical Medicine, had authorisecJ 

 him to make an experiment to show the practicability of 

 preventing malaria by easily applied means. A hut was- 

 to be erected in the most malarious part of the Roman 

 Campagna with wire gauze doors and windows so as to- 

 render it mosquito proof. This hut two skilled observers 

 were to occupy from May to October, that is, during 

 the whole malarial season. By day they would be 

 able to go out, but at sunset, before the mosquitoes rose^ 

 they were to enter their hut and remain closed in until 

 daybreak. By this means it was contended they would 

 be free from all possibility of infection by mosquitoes. In 

 accordance with this plan Drs. Low and Sambon, or 

 London, took up their residence in June, and the latest 

 information is that they have passed through a trying 

 ordeal unscathed and without any appearance of fever. 

 This experiment is of great value, .though open to- 

 criticism on the grounds that the conditions are somewhat 

 artificial. 



A similar experiment, under more natural conditions^ 

 and therefore, perhaps, of a more searching character, 

 has been tried by the members of the second Liverpool' 

 expedition to West Africa. For four months, in the 

 most malarious districts on the Niger, Drs. Annett, Dutton 

 and Elliott have lived, relying, not on quinine, but only 

 on their proper use of mosquito curtains. A recent com- 

 munication shows that they have retained their health- 

 throughout their stay. 



Another important experiment has recently been tried,, 

 an experiment which may be considered the complement 

 of those just mentioned. 



A consignment of Anopheles, fed on the blood of a 

 patient in Rome known to contain parasites, was received 

 in London from Prof. Bastianelli in July last. A son of 

 Dr. Manson, who had not been in a malarious country- 

 since childhood, submitted himself to the bites of these 

 infected mosquitoes. Within a fortnight Mr. Manson 

 had a typical attack of fever, and in his blood were found 

 parasites similar to those causing the fever of the Romar> 

 patient on whom the mosquitoes had originally been fed. 



This is a crucial experiment, and proves to the hilt, if 

 further proof were needed, that malaria is conveyed by 

 mosquitoes from man to man. Similar " feeding " ex- 

 periments had been done before, but never has such a 

 striking and satisfactory demonstration been obtained. 

 We have now to deal no longer with theories, but with 

 facts, and it remains to put into practice the valuable- 

 information we have obtained as to the possibility of 

 limiting malaria, and so improve the sanitary condition,, 

 and thereby increase the commercial prosperity of many 

 of our greatest colonies. R. Fielding-Ould. 



THE GEOLOGICAL SURVEY OF GREAT 

 BRITAIN AND IRELAND^ 



THE summary of progress of the Geological Survey of 

 the United Kingdom for the year 1899 has been 

 issued by Sir Archibald Geikie, Director-General. The 

 field-work was carried out in England and Wales 

 principally in the coal districts and bordering tracts of 

 North Staffordshire, Leicestershire and Glamorganshire ;. 

 in the slate and granite areas of Cornwall ; and in the 

 Cretaceous and Tertiary regions of the southern and 

 southern-midland counties. In Scotland the survey of 

 the Highland regions was prosecuted as vigorously as the 

 nature of the ground permitted, and progress was also 

 made in the surveys of Arran and Skye. In Ireland the 

 revision of Silurian areas was continued. 



The bulk of the summary is taken up with a somewhat 

 detailed record of the observations made in the field ; and 



1 " Summary of Progressof the Geological Survey of the United Kingdom- 

 for 1899." Pp. V+214. (London: Printed for H.M. Stationery Omce,- 

 1900.) 



