December 20, 1902.]
malaria, as there may be one not yet experi- mented with; but the probabilities are so great as to amount to practical certainty.
Now as regards Hongkong. The first is manifestly impossible among & population whose constituents are changing by the thous- and every day through the Canton and other local steamers; the second is equally out of the question as a public measure, though much may may be done in the way of personal prophylaxis by the careful use of mosquito-netting, and, in special circumstances, the use of wire gauze protection of doors, windows, and verandahs; but the third measure is, I claim, entirely possible and thoroughly pacticable, could sufficient public opinion demanding it be aroused to allow of efficient legislation on the subject. Let every nullah in and near the city be given a perfectly smooth floor by careful training; let the Sanitary Board be given authority to treat every collection of stagnant water, whether it be an oozing from the hillside or a rain-collec- tion in an old flowerpot, as a nuisance, to be dealt with as other nuisances are dealt with; let a sufficient staff be provided to carry into effect the new bye-laws; let it be thus rendered im- possible for mosquitoes to find breeding-places within the precincts of the city; and anopheles and culex alike would disappear from this city
CHINA OVERLAND TRADE REPORT.
I hold, sir, no brief to advertise this Company. | been saturated with quinine, until as the years I have directed attention to the paragraph I have passed fewer and fewer anopheles have have read in order that I may point out to this been infected, most of those that exist are It follows then that malaria would entirely representative meeting that from the first of harmless, and malaria is nearly extinct. But and finally disappear if any one of three next March Hongkong will be in direct com. the building of a house in such a Peak dis- measures could be efficiently carried into effect:munication with one of the great endemic cen- trict as I have supposed introduces an entirely -1. If the blood of all malarious persons could tres of yellow fever, aud we may any day there-
new factor. The first public indication of the be disinfected, say by quinine. 2. If all healthy after have yellow fever landed on our shores. new scheme is the erection of a big matshed, mosquitoes could be prevented from biting And, as I have said, we have the appropriate and the importation of a crowd of Chinese infected persons; or if infected mosquitoes could culex, Stegomyai, ready to carry it from man coolies, who spend the night as well as the day be prevented from biting healthy persons. 3. If to man, a mosquito which from its day-feeding in the hitherto non-malarious district. I have all anopheles mosquitoes could be destroyed. habits is more difficult to reckon with than not had occasion to mention that the crescentic Unfortunately no one of the three is capable anopheles. Now let me show the converse of mosquito-infecting form of the parasite malaria of sufficiently universal application; and it all this. Yellow fever has been endemic in is extremely resistant, and persists in the blood remains in any given locality to apply the Havana continuously thoughout its history. Yel- of a person who has suffered from n alaria for general principles stated as may seem most low fever has been to it always what bubonic long periods after all trace of the fever, has likely to reduce malaria to a minimum, or cause plague has been to Hongkong in recent years, disappeared. There are thonsands of people its entire disappearance, in that locality. thongh not so fatal. There were during 1900, walking the streets of Hongkong to-day show- 1,244 cases of yellow fever, with 310 deaths. ing no symptoms of malaria, yet infective to In February of last year the authorities of mosquitoes through the crescents in their blood; Harana resolved to act on the mosquito theory In any crowd of coolies, therefore, it is almost of its origin, and to take measures to abolish it, a foregone conclusion that some of them are Extract from the Medical Review of October, malaria-infected. Our hitherto harmless Peak 1902.7 An ordinance was issued requiring anopheles feed on them, ingest the parasite, all people within city limits to keep receptacles and become themselves infective. So it comes containing water mosquito-proof. The city about that a few weeks after the commencement was divided into districts. An inspector was of earth-cutting for the new building cases of appointed for each, under whose directions oil fever begin to show themselves in the houses was poured into all puddles, cess-pools, etc, and in the neighbourhood, especially among the after sufficent notice had been given all recept children who are more suceptible to marlaria, acles in which larvae were found were destroyed. and such cises continue to occur throughout All persons having larve on their premises were the operations, and for a short time after. fined. To prevent the Stegomyai from biting Then the gang of coolies disappear from the infected persons, the hospitals and bouses in locality, the residents quinimise themselves which there were cases of yellow fever was and their servants who may have suffered, thoroughly screened. To kill the infect d and the infected mosquitoes die out, and con- mosquitoes the infected building was dusted from ditions return to their normal. top to bottom with pyrethrum powder.
cutting is over: the fever is The mosquitoes were carefully swept up and earth-cutting, sir, had nothing to do with destroyed. The houses contiguous to the the fever: it was a mere accident of the situation. infected house were treated in the same way lest The recent severe epidemic of malaria in the infected mosquitoes had escaped to them. The region surrounding MacDonnell Road I at- tribute to no other cause than this. Anopheles reporting of yellow fever was made com pulsory.' What was the result of all this? were breeding in these ravines in the past in The destruction of mosquitoes was begun on swarms, as they still are where measures against 27th February. In March there were only 2 them are not being adopted; but the extensive cages. No other case occurred until 20th April. building operations above MacDonnell Road, This condition had never been approximated with the crowds of Chinese coolies introduced, before in Havana. The total of cases after that have made them now infected mosquitoes. The was:-April 2, May 4, June 0, July 4. August building operatious must go on; the crowds of 6. September 1, and in October, November and coolies are essential; the remedy is, destroy the December, 1901, and January of the present mosquitoes-and this can be done. I have year not a single case occurred. What was done urged' that in addition to the ravines and the in Havana a year ago can be done in Hong-waterpools throughout the district being dealt kong, in view of malaria and the filari diseases present with us, and to anticipate yellow fever. Meanwhile, until the lawshall step in, as step in it will one day, to compel the abolition of stagnant water," let me urge for reasons of personal interest the systematic inspection of premises for the presence of " wrigglers" in water. It is undoubted that mosquitoes that infest any house have been bred on the spot, in such receptacles as old flowerpots, broken dishes, empty water-tanks, tire-buckets, the plates auder florerstands, under the ice-chest to catch the drippings, under the feet of furniture to prevent the approach of ants, and such like. An inspection once a week is sufficient to effectually stop the breeding of mosquitoes in any locality.
of Victoria.
Let me briefly show reason for my plea that culex as well as anopheles should be exter- minated. There is among the Chinese of this. neighbourhood a disease, or rather a group of diseases, the most striking of which is elephan- tiasis, where a limb or other part of the body becomes bugely hypertrophied, and life becomes a burden from the sheer weight of the part affected. These diseases are due to the presence in lymph vessels of a parasitic worm, the young of which appear in the blood stream as the minute blood worm, one of whose names is the Filaria sanguinis hominis, the thread-worm of the human blood. Now this blood-worm is trans- mitted from one human being to another by a culex mosquito, Culex Fatigans, one of the brown forms of mosquito so common in the early evening in this Colony. The details differ somewhat, but practically transmission takes place just as malaria ia transmitted by ano- pheles. Again, yellow fever has now been traced equally definitely to a Culex Fasciatus as the transmitting agent. It is simply a variety of the black-and-white striped "tiger" mosquito that gives us so much trouble in the day time, Culex Scutellaris. Theobald, the entomologist at the British Museum, has recently broken up the old calex genus, and he includes these two insects in a new small genus, Stegomyia, describing them as the Stegomyia Fasciata and the Stegomyia scuttellaria." I find that the habits of Scutellaris here exactly cor- respond with those of S. Fusciata in the regions where yellow fever prevails; and what I want to point out is, that if yellow
fever should visit Hongkong, we have a mosquito swarming in the Colony which can cause it to become epidemic. We are apt to think of yellow fever as the scourge of the far-away West Indies and Central America, and not to be reckoned with hero. Let me read to you a paragraph that appeared in our local papers so recently as December 4th (Daily Press):-"A new shipping line in Hongkong. China Commercial $.8. Co., Ld. We are informed that the 'China Commercial 8.8. Co., which was incorporated in Hongkong on 1st November, will inaugurate a service between this port and Mexico at the beginning of March next. The Company's steamers will carry both freight and passengers, and a monthly service will be maintained between Hongkong and the Mexican ports."
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The earth- The gone.
with, there should be a general fumigation of all basements, boxrooms, servants' quarters, &c, in this locality with chlorine gas in course of, the winter, for the destruction of adult insects, which tend to hibernate in such places. It is a mistake to suppose the mosquito the créature of a day. It lives for months, and there is a modified hibernation, fertilised females living in a quiescent state throughout the early winter, ready to lay their eggs in spring.
And now let me invite your attention to the practical demonstration I have proposed. Under the microscopes you will find specimens of the parasites of malaria, of halteridium in the blood of a pigeon, of the blood-worm. Filaria of the important sanguinis hominis, and distinguishing features of the two great mos- Dr. Hunter and Dr. Pearse have quito groups. kindly promised to stand by the microscope table for reference if anything should not be A touch or a shake is sufficient to put a And I high-power microscope out of focus. shall be glad if anyone who fails to see what is said to be seeable will at once direct attention to it, that the matter may be rectified by one of these gentlemen or myself. On the second table I have placed pictures and photographs illustrating much of what I have been saying, and showing one or two of the workers in this field of science whose names I have mentioned. Ijalso submit for your inspection a few of the . works on malaria and mosquitoes, both more elementary and more abstruse, for the informa- tion of those who may wish to go into the ques- Some of them at lea-t are in tion more fully.
On the third table will be stock locally. found specimens of the mosquito in all its stages, pinned specimens, loose specimens, and living specimens. All the living specimens are safely muzzled! My chief aim in arranging this part of my demonstration has been to facilitate comparison between anopheles and culex, and to enable you to train the eye to
Before we turn to the practical demonstration I would like to refer to the connection of malaria with earth-cutting. Explanations of a far-fetched character, into which I shall not enter, have been offered; but so far as Hong-clear. kong is concerned the following is the probable explanation of what until recently was very mysterions. Let us consider the case of a new building being erected at the Peak, in a part of the Peak where in ordinary times malaria is unknown. This absence of fever is not entirely due to the absence of the anopheles mosquitoes, for they breed in the ravines at the Peak as well as elsewhere. But in ordinary circum- stances the locality is peopled by Europeans, or Chinese, who have been long associated with Europeans, and who, when they have previously suffered from malaria, have had their blood cleared of the parasite by the use of quinine. The conditions, in fact, are pretty much what they are in many parts of England, where, anopheles are present and formerly worked havoc among the population. James I. of England and Oliver Cromwell. the rotector, both died of malarial fever. But in England drainage has reduced the number of mosquitoes, and the malarious part of the population has
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