INSECT PESTS.

Hokitika Guardian, 5 November 1925, Page 3

INSECT PESTS.

THE CONQUEST OF DISEASE.

Sir Ronald Ross recently performed the opening ceremony of the new building for the Alosquito Control Institute at Hayling Island. Five years ago a very serious plague of mosquitoes in South Hampshire led to concerted measures for control by the draining of stagnant water and other methods, and one result was the establishment. of the institute, with Dr J. F’. Alarshall as its director. The efforts undertaken to abate the plague have been very successful, and recently Dr Marshall described the work of the institute in a pa]>er read before th(> British Association at Southampton. When the new building was opened by Sir Ronald Ross many members of the British Association were

s present. lii an interview with an "Observer’' 1 representative. Sir Ronald Ross said: "Our work lor the general extonnin- - ation of insect pests is designed chiefly ■- for the protection of towns and cities. We cannot expect —indeed, there is no need—-to drive mosquitoes and the like out of jungles and marshy tracts away from civilisation. The area of (light 1 of noxious insects has been shown by • repeated tests to lie strictly limited, ’ extending to a very few miles at the most. "From a purely economic point of view, quite apart from humanitarian grounds, it would lie far cheaper for Government:, and local public bodies as well as individuals, to contribute to preventive and research work, such as is going on m Hayling Island and elsewhere. The amount of sickness and deatli averted would he out of all proportion to the cost. "It would he quite feasible for a rich country to put down a large sum of money for dealing with these insect pests lather than spend a hundred limes as much—and this is done readily enough for killing "II a few human adversaries. Why, the money spent on a single dreadnought would simply work wonders if applied in this way.” DISEASE CARRIERS. Insects were first proved to he carriers of disease in the second half of the last century. The late Sir Rat rick Malison showed that a tropical parasite of man, called Maria, was conveyed by a species of Culex mosquito. This was a very important discovery, as the parasite causes the terrible disease known as olephanlitis in many tropical countries. In the 'nineties some American observers found that Texas cattle fever is carried in- a tick, and Sir David Bruce, late President of the British Association, showed that the widespread Nngana disease of African cattle was due to trypanosomes carried by the tsetse fly. and inoculated by its bite. In ISStI Dr A. Laveran discovered that what is. perhaps, the most important of all human diseases, viz., malarial fever, is caused by a little parasite in the blood of mail. This disease, had always been connected, fmm Ihe lime of the ancient Romans, and possibly of the Greeks, with stagnant water on till* ground, and lip to ltd). - ) every medi< a I seientist, ineiiiding Dr M.ansnn suspected that- it might be carried ill some way by mosquitoes. This was proved to be the case bv Sir Ronald Ross between the years Is!15 ami 1899, as the result of a long series oi investigations carried out in India, llis conclusion was verified and extended—in Italy chictlv by Dr A. Bigiiaini, in 1 Africa by Ill's Daniels. Stephens, and ' Christophers, and elsewhere by other enthusiastic workers too numerous to 1 mention. Largely in consequence ol this discovery, Schools ot Tropical Medicine were lounded in I Sill) at Liv- 1 crpool and in London tor the purpose 1 of leaching the new knowledge and : promoting further studies. 1 .MOSQUITOES AND YELLOW FEYKR ’ Early in !!)0I the American doctors • Rood. Carroll. Luzonr and Agramonle ' verified the previou- hypothesis of Dr I ('. Finlay, of Havana, that mosquitoes also carry yellow Icier. Malaria i’ ' carried by various species of the genm i of imisquiUH:-* called anopheles, where- < as yellow fever is carried by the Steg- t moyia ; but tlm breeding habits of all ] these insects being different; require i. very careful investigation. Sir Ronald Ross curried out his work ! not for entomological, but for sanitary i reasons. From 1899 onwards be paid ! visits to nine different countries or • colonies with a view to urging the re- ( duct-ion of malaria-hearing mosquitoes in them: and other methods of prevention. such as the use of mosquito nets and—as regards malaria —ol quinine, were advocated by him and by others. But although this matter has now been , placed fully and frequently before the ( public for more than a quarter of a , century, the progress made in response ( to scientific advice continues to he very slow. Almost the first actual proof of malaria being affected by "mosquito reduction”—now often called "mosquito control'’ -was given in the French town of Ismailia, on the Suez Tamil, 111 ltio.'l. Oil the advice of Sir Ronald Ross and Sir William MacGregor. Governor of Lagos, who accompanied him to that town, which was entirely rid of the disease within a few months. HOW PANAMA WAS MADE HEALTHY. The Americans had meanwhile already started mosquito control ill Havana, against both yellow fever and malaria, as was first recommended by Sir Ronald Ross in 1809. In 1901 Americans began the construction ol the Panama Canal, and by means ol this now system ol prophylaxis they wore able to complete it without the immense loss of life previously experienced by the French from yellow fever and Malaria. Colonel Gorges was the head of the sanitary department in l u ,th Havana and Panama, and his admirable methods are famous throughout the world. British attempts at the control ol malaria have been making headway only very slowly. This may he due to the fact that sucli efforts have been local for the greater part. 'Special mention must be made in speaking of British efforts of the work of Dr Clark at Hong Kong and of Sir Malcolm Watson and others in the Federated Mnlav States. THE WORK AT HAYLING ISLAND. |) r Marshall has been assisted in his research, work during the last five years by Sir Richard Gregory (editor of "Nature”) and other residents. They have also been greatly helped by Colonel S. P. James, of the Ministry of Health, and Mr K. W. Edwards, of the British Museum. The results have been remarkably good. The Ministry of Health, the Havana Rural District Council, and many local residents have subscribed towards the tost of the somewhat extensive measures required. Another centre doing a cognate work is the Ross Institute and Hospital for Tropical Disease. Putney Heath. Recently founded by Sir Mililam Simpson and Dr Aldo C’astellani, with Sir C harles -McLeod, Bart., as chairman, it I w jll be opened almost immediately. Sir Ronald Ross is the Director-in-C’hief of this institute, which lias been founded by public subscription, aided by <,rants from some tropical -Govern- . i nients.