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THE DISEASE-BEARING INSECTS IN RURAL

HYGIENE.

By HARVEY B. BASHORE, M. D.

The study of disease-bearing insects is of special interest to the rural sanitarian, for both of these insect families flourish more in the country than in the city; one of them, the malarial-bearing mosquito, is pre-eminently a rural dweller.

The well-drained city house, situated on an elevated avenue, with its covered garbage can, quick disposal of its contents and properly screened kitchen, suffers very little from either of these pests. On the other hand, the village and country house very often swarm with both; the uncovered manure pile and decaying garbage teem with flies; the country rain-barrel and neglected drainage furnish breeding places for myriads of mosquitoes.

One great point about the life history of the fly and mosquito is that they are "born and bred," more or less, on the premises where they are found. Each householder is responsible to a certain degree for his own flies and mosquitoes. It would be well worth while to use every endeavor to eliminate these pests if for that alone, but as they are now known to carry disease, the subject becomes of vital interest to all.

Of all the sanitary appliances used in the country the earthcloset is of especial interest on account of the likelihood of being a breeding place for flies. Last year I raised some flies from the larva of an earth-closet and found that there were two principal varieties, namely, the sarcophaga, and a stable fly; both or either of these may carry disease for they are known to frequent kitchens. Earth-closets should therefore have tightly fitting covers, and if so arranged the breeding of flies in them will be reduced to a minimum, as I found by actual experiment.

The garbage hole in the garden bed, which I have frequently recommended as a method of disposal, unless covered with earth very carefully and very frequently is likely to become a breeding place; to avoid this I tried screening the hole, but found that the little fruit flies, which are particularly fond of garbage and fruit, actually crawled through the meshes of the screen, so I resorted to a tight board cover and flies were eliminated from that place at least.

The village manure pile which we used to think ought to be exposed to the sun to favor nitrification, should be covered 'or screened, for many of the manure-loving flies frequent houses.

The village rain-barrel is without doubt one of the great breeding places for mosquitoes, except the malarial-bearing anopheles, which, I am sure, must wander some distance from its birthplace. The locality where I made investigation last year had all three of the anopheles family, yet I could find no possible breeding place within at least several hundred yards.

In a very wild and beautiful valley not far from my home I found larva of anopheles in the little rock pools, and by keeping them in bottles reared the adult-A. punctipennis.

In another instance I found them in many pools in the bed of a new railroad cutting; this would perhaps explain why railroad grading is so frequently coincident with malaria.

The country privy and cesspool is also a great breeding place of culex, and all such places should be treated with kerosene during the mosquito season.

I tried this plan, with screening of cistern, etc., in a village house, and found that there was a great diminution of the insects.

The value of small fish-goldfish and sunfish-in keeping ponds free of mosquitoes is very great. I put some catfish in a bycket containing mosquito larva and all larva had disappeared twentyfour hours after the introduction of the fish. The fact that catfish will destroy larva is interesting, because some ponds and pools are so muddy and filthy that goldfish and sunfish will not thrive; in such, catfish would seem to be the remedy.

THE PROPHYLACTIC TREATMENT OF TYPHOID

FEVER.

We have read with very great interest in the "British Medical Journal" of September 27, 1902, a most valuable paper by Major Firth and Major Horrocks, of the British army, upon the influence of soil, fabrics and flies in the dissemination of enteric infection. The object of their research is well described in the title of their paper, and the experiments themselves seem to have been carried out with the greatest possible care, all collateral influences being carefully considered. Altogether thirty-six experiments were performed, and the conclusions which they reached may be summed

up as follows. We use their own words to express the results which they have obtained:

"From our experiments we draw the following conclusions, which are equally applicable to enteric bacilli recently isolated from enteric stools, as to old cultures of the organism which have been in the laboratory for many months.

"1. That there is no evidence to show that the enteric bacillus, when placed in soil, displays any disposition or ability to either increase in numbers or grow upward, downward, or laterally.

"2. That the enteric bacillus can be washed through at least eighteen inches of soil by means of water, even when the soil is closely packed down and no fissures or cracks allowed to exist.

"3. That the enteric bacillus is able to assume a vegetative existence in ordinary and sewage polluted soil and survive therein for varying periods, amounting in some cases to as much as seventy-four days.

"4. That the presence or absence of organic nutritive material in the soil appears to be a largely negligible factor, since the enteric bacillus can survive in a soil indifferently well whether it be an organically polluted soil or a virgin soil, and whether it receive dilute sewage or merely rain-water.

"5. That an excess or great deficiency of moisture in soils appears to be the dominant factor affecting the chances of survival. of the enteric bacillus in, or at least the possibility of recovering it from, soil.

"6. That from fine sand allowed to become dry, the enteric bacillus can be recovered on the twenty-fifth day after inoculation.

"7. That from fine sand kept moist with either rain or dilute sewage, the enteric bacillus cannot be recovered later than the twelfth day after fouling; this inability to recover the organism is due probably not so much to its death as to its being washed down into the deeper sand layers by liquids added.

"8. That in peat the enteric bacillus appears to rapidly die out, as the microbe cannot be recovered from it after the thirteenth day; but this soil is so porous that it is quite possible that the microorganism was washed down into the deeper parts and consequently not recoverable from the place of inoculation.

"9. That from ordinary soil kept damp by occasional additions of rain-water the enteric bacillus can be recovered up to and on the sixty-seventh day.

"10. That from a similar soil kept damp by occasional additions

of dilute raw sewage, the enteric bacillus is recoverable up to the fifty-third day.

"11. That from a similar soil kept damp by occasional additions of dilute sterile sewage, the enteric bacillus is recoverable up to the seventy-fourth day.

"12. That in similar soil, after heavy rainfalls, the enteric bacillus at once disappears from the surface layers.

"13. That from a similar soil, allowed after inoculation to become so dry as to be readily blown about as dust, the enteric bacillus can be recovered up to and on the twenty-fifth day; and that enteric infective material can be readily translated from dried soil and sand by means of winds and air currents.

"14. That in a sewage-polluted soil recovered from beneath a broken drain, the enteric bacillus is able to survive up to the sixty-fifth day.

"15. That from a piece of khaki drill, inoculated with an emulsion of the enteric bacillus and then allowed to become quite dry, the microorganism is recoverable up to and on the seventyfourth day.

"16. That from a piece of khaki serge, similarly treated, the enteric bacillus is recoverable up to and on the eighty-seventh day. "17. That from a piece of blue serge, similarly treated, the enteric bacillus is recoverable on the seventy-eighth day.

"18. That from a piece of khaki drill fouled by liquid enteric feces and then aliowed to dry, the microorganism is recoverable on the seventeenth day.

"19. That from similar fabric fouled by solid or semi-solid enteric feces and then allowed to dry, the microorganism is recoverable up to the ninth day.

"20. That the enteric bacillus is able to survive in surface soil an exposure of 122 hours of direct sunshine, extending over a period of twenty-one consecutive days. That from a piece of infected serge the enteric bacillus is recoverable after the fabric has been exposed to fifty hours of direct sunshine spread over a period of ten days.

"21. That ordinary house flies (Musca domestica) can convey enteric infective matter from specific excreta or other polluted material to objects on which they may walk, rest, or feed. That such infective matter appears to be attached not only to their heads (mandibles probably), but also to their legs, wings and bodies. It has not been proved that the enteric bacillus passes through the digestive tract of the fly."

All these conclusions possess a prophylactic value difficult to estimate, since they add much to our conception of the means by which typhoid infection is spread, and emphasize the necessity of seeing to it that all excreta of the patient are destroyed as soon as they escape from the bladder or bowel. Too frequently this immediate disinfection is not carried out, and physicians and nurses grow careless of the needs of a germicide used at the earliest possible moment.-"Therapeutic Gazette," Nov., 1902.

OPEN LETTERS ON VIVISECTION.

HON. JACOB H. GALLINGER, Chairman of the Senate Committee on the District of Columbia, Washington, D. C.

MY DEAR SIR: As you have repeatedly introduced bills into the Senate for the purpose nominally of regulating experiments upon animals in the District of Columbia, which bills, however, if they had become laws, would, in fact, have prohibited many, if not all of them, I deem it my duty to call your attention to the case of Midshipman Aikin of the United States Naval Academy, who was recently injured in a football game. My reason for doing so is to show you by a single concrete example that knowledge gained by animal experimentation is an immense boon to humanity and that, therefore, such experiments should be heartily encouraged.

The facts of Mr. Aikin's case are as follows: When I first saw him, three days after the accident, I found that he had been unconscious for a half hour after the accident and ever since then had complained bitterly of headache, which he located always in the forehead. Mentally he was very dull, though not comatose. His pulse was slowed down to 52 instead of being 72, the normal. Soon after the accident he began to develop convulsions, first in the right leg, afterward in the right arm also, the right arm being finally the chief seat of the convulsions. When they were very severe they involved the left side also. The face was never involved. In six and one-half hours after I first saw him he had twenty-four of these attacks, all limited to the right arm. They were not attended by any loss of consciousness. They exhausted him very greatly, especially when they were excessively severe. Several times it was necessary to give him chloroform.

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