The hospital will benefit to the extent of £1,000 by the will of the late Mr. Samuel Lewis.

*

Surgeon H. L. Norris, of the Royal Naval Medical Service, has been promoted to be Staff Surgeon.

A. G. J. Thompson, M.B., B.Ch., Oxon, has been appointed clinical assistant to the Chelsea Hospital for Women.

B. Poulton, M.D., has been appointed honorary surgeon to the Adelaide Hospital.

W. C. Mence, M.R.C.S., L.R.C.P., has been appointed certifying surgeon under the Factory Act for the Perranporth division of the county of Cornwall.

F. A. Brodribb, M.R.C.S., L.R.C.P., has been appointed district medical officer of the Bradfield Union, Berks.

*

J. R. L. Woods, M.R.C S., L.R.C.P., has been appointed district medical officer of the Forden Union.

*

A. C. Hudson, M.D., B.C., F.R.C.S., has been appointed second house surgeon at the Royal London Ophthalmic Hospital, City Road, N.

T. G. Longstaff has been granted the M.D. degree in the University of Oxford.

S. G. Macdonald has been granted the M.B. degree in the University of Cambridge.

Some Observations on the Breeding Ground of the Common House-fly and a Description of a Species of Moth-fly.*

By G. D. FRANKLIN, B.A., M.B., B.C. (Cantab.), Captain I.M.S. Medical Officer, 8th Gurkha Rifles, Shillong.

FOR

OR the last nine months I have been carrying out a series of experiments with a view to determining the breeding ground of "Musca," the common house-fly.

The method of procedure has been as follows:

Wide-mouth bottles have been one-quarter filled with the material to be experimented with, and the mouth then closed by a piece of gauze tied with string.

The bottles were kept in a warm room during the night and put out in the sun during the day.

The material experimented with, was selected either because it actually contained larvæ, or because in the situation from which the material was taken, flies were found in large numbers.

Early in the experiments, it was observed that if the material selected was allowed to get dry, or if too dry material was selected originally, that the experiment gave a negative result.

In Shillong the cantonment trenching is carried out on the top of a hill, the soil of which is sandy and very dry.

This accounts, I think, for the negative result obtained in all the experiments carried out with material from this trenching ground. Four experiments were also made with night-soil, which had been trenched, and after a month dug up, and exposed to the air for 48 hours. It had undergone partial disintegration, but was still moist when first exposed. However, it apparently either dried too rapidly after exposure, or else had lost some special constituent or constituents, as it failed to serve as a breeding ground, and the four experiments gave negative results. At the same time material taken from various places, where latrine buckets were washed, and where there would be night-soil in a very liquid condition, in every experiment yielded positive results, "Musca," the house-fly being hatched out. This, in conjunction with the fact that "Musca" was not obtained, except extremely rarely, and then only single specimens, from other situations, such as near cookhouses, on dust

*

Reprinted from The Indian Medical Gazette, Vol. XLI. No. 9, September, 1906.

heaps, etc., where the adult insect was found in great numbers, and where one would have expected that the house-fly would breed, lead one to suppose that night-soil was the material in which the house-fly commonly breeds, and that these other situations were only feeding grounds. With a view to testing this supposition, some night-soil was taken straight from latrine buckets and collected into a large flat receptacle. This was exposed to the air. In four days' time this night-soil was found to be swarming with larvæ. These larvæ were about 42 of an inch long; they were yellowish in colour, extremely active but with no distinct head. Within a period of 36 hours to one week these larvæ became pupæ.

These pupa were about 3 of an inch long. They were light brown in colour at first, and gradually became darker till they were ultimately a deep dark brown.

The puparium was opaque, thick and brittle. A soft tissue paper-like inner coat could be distinguished at the cut surface. In eight days' time a fly emerged through a circular opening in the anterior end of the puparium. In the case of this same fly exactly eight days elapsed in the pupal stage in three other experiments.

This fly on examination was seen to be black with yellowish markings. It was of the size of the common house-fly.

The arista were flumose. The proboscis rounded and not adapted for piercing.

The curvature of the 4th vein was angular. The halteres were covered with a squama. The abdomen was composed of four indistinct segments, yellowish in colour and non-metallic. These are the characteristics of "Musca," the common house-fly.

At the same time numerous experiments were made with material from other situations where "Musca" abounds, but they were almost, without exception, negative so far as this particular species was concerned.

So far then as these experiments have been carried out to the present, they go to show that the breeding place of the common house-fly is in night-soil, and that these other places, such as refuse, heaps, etc., where the imago abounds, are only their feeding grounds. In the light of these facts and bearing in mind the capability of these flies of conveying bacteria, it would appear desirable to inhibit their growth as much as possible. For although one cannot say definitely that the common house-fly breeds only in night-soil, at any rate it breeds in great profusion in it and not in other situations where one would expect it to. I found that if night-soil was spread out thinly on a tray and allowed to dry quickly, that no growth occurred, and that even if the night-soil so

B

experimented with, already contained larvæ, that these died when the night-soil became dry. The addition of lime or perchloride of mercury also inhibited the breeding. With a view to at any rate diminishing the number of these flies and at the same time lessening the dangers which they, with their power of conveying bacteria, threaten, the treatment of all night-soil with either lime or perchloride of mercury, both of which are equally efficacious, seems to be a measure worthy of consideration.

It is too early in these experiments to lay down hard and fast rules, but there is, I consider, sufficient evidence to state that the common house-fly breeds in great profusion in night-soil and not in the vicinity of cook-houses, etc., where it is to be found in such vast numbers. These latter situations being apparently only its feeding grounds.

In the course of these experiments I have come across a species of the Psychodidæ (the moth-flies or owl midges, as they have been called), which, I believe, has not been described previously.

This moth-fly has been hatched out constantly from material taken from the neighbourhood of cook-houses, such as is found in the drain at the back of cook-houses.

The process of development from larva to imago is completed within 24 hours.

The larva is a whitish cylindrical maggot, active and about 4 of an inch long. It possesses a distinct head. There is a terminal breathing tube. All the internal organs can be clearly distinguished under the low power.

The pupa is about 29 of an inch long. There are well marked stigmata. The anterior part is dark brown, and the remainder regularly streaked dark and light brown. Under the low power various parts of the imago can be distinguished.

The puparium is burst irregularly at the anterior end, below and between the stigmata. It is brittle and thin and presents a streaked appearance.

The imago emerges from the puparium head first. It comes out quickly and at once begins to spread its wings. Even before this process is completed, it will sometimes run some little distance; and generally it runs some distance before taking flight. These flies are strong runners and moderate fliers; in the way that they suddenly, as it were, jump up, they remind one of the "skipper" butterfly; but their flight is of short duration and they quickly settle again.

The imago is about 12 of an inch long and presents a stumpy appearance, its breadth being considerable. Even when

looked at only with the naked eye, it presents a furry appearance. The wings are of a dark silvery grey colour, and the body more brownish.

The antennæ are easily seen. They have a bright silvery appearance. Under the low power, 13 segments can be distinguished, which are somewhat "heart" shaped. These segments gradually diminish in size towards the tip. Numerous long hairs spring from each segment, all trending anteriorly.

The proboscis is short.

The palpi are composed of four segments, on which the hairs are numerous, but short and spikey.

There is a thick bunch of hair on the occiput.

The thorax is short and thickly covered with hairs. The legs are comparatively short and sturdy. They are fairly regularly covered with shortish hairs; the terminal claw is small.

The wings are broad in comparison with their length. They are thickly covered with hair, and there is a long and very distinct fringe of hair round each wing. There are two well marked tufts of hair on the anterior margin of each wing, near the body. The first longitudinal vein is simple, the second forked, the third simple, the fourth forked, and the fifth, sixth and seventh simple. When not in use the wings lie in a slanting position on each side of the body.

The abdomen is broad, and composed of seven segments. The hairs on it are collected into stout tufts. The hairs all over the body are considerably coarser than those on the wings.

The external genitalia can be distinguished.

Experiments were made with these flies, with a view to determining their power of conveying bacteria. The bacterium experimented with was the bacillus typhosus. Two plates of earth were sterilised. One of these was infected with a pure culture of the bacillus typhosus. They were then placed some distance apart in a gauze cage, with a glass window. Some pupa of the moth-fly were then introduced in a watch glass. When the flies emerged from the puparia, they could be seen flying backwards and forwards between the two plates of earth. After two days the flies were killed, and a culture tube inoculated from the formerly uninfected plate. In four days' time the appearance of the culture tube was as shown in the figure.*

A sub-culture made from the areas marked A and B, resulted in an apparently pure growth of the bacillus typhosus being obtained.

It is unfortunately impossible, on financial grounds, to re-produce the plates which illustrated the original article.