Sessional_Paper_1902 — Page 828

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The results were as follows: Snowflake.-On adding one teaspoonful to 13 gallons of water in a circular vessel teeming with larvæ, we found that they were all dead in two hours.

Comet.-Under the same conditions no larvæ were dead in two hours, although they were much less active, in 10 hours they were all dead.

300° Mineral Colza.-A few of the larva were dead in two hours, several alive after 24 hours. On adding a tablespoonful instead of a teaspoonful to the water, the following results were obtained

Snowflake.—All the larva were dead in ten minutes.

Comnet. About same effect as a teaspoonful of Snowflake.

Colza.-A number alive after six hours.

Snowflake is much more destructive than Comet, it also spreads more rapidly on the surface of the water; with the Colza the oil does not spread so well on the water.

One tablespoonful of Snowflake was tried in a water run round a cress bed and all the larva sank within 5 minutes.

In stagnant water Jeye's fluid is by far the most effectual larvicide, one teaspoonful to 14 gallons of water with the same surface as was used before killed the larvæ in 2 minutes.

Twenty drops in the same quantity of water killed them all in six hours, it also has this effect that it kills all the larva in the water whereas the oils only kill those on the surface, it is useless in running water as it mixes with it and does not float on the surfaces.

To show the difficulty there is in ridding certain neighbourhoods of this Colony of anopheles I would refer to the extensive operations carried on in the spring of last year at the Military sanatorium, Magazine Gap, at the suggestion of Dr. YOUNG, a Civil Medical Officer attached to the China Expedi- tionary Force, to free this place of malarial fever.

Two hundred men of the Indian Regiment were detailed to carry out the necessary work under Dr. Young's supervision, the hills were cleared for a distance of 300 yards of all brushwood and under- growth, several bogs were drained and the anopheles pools in the nullah were filled up.

Notwithstanding all these measures, however, fever was so prevalent there in the autumn months that the station had to be vacated by the Troops.

NEW TERRITORY.

Dr. Ho NAI Hor has continued to reside at Tai Po and has performed the duties of Resident Medical Officer in the New Territory, the distances he has to travel are very great and it is practically- impossible for him to do justice to the large resident population there, the question of appointing another medical officer to reside in the West of the New Territory say somewhere in the Shap-Pat- Heung Valley will soon have to be considered. I attach the annual report on the work of the medical department in the New Territory.

In an Appendix I give a report by Dr. THOMSON regarding the mosquitoes which occur in the Colony of Hongkong, this has entailed an immense amount of labour and has, as was to be expect- ed, confirmed the fact that where malarial fever is rife there anopheles abound.

In Appendix is given the notes of several cases of interest which have occurred in the Hospital during the year.

Appendix B contains the report by Dr. THOMSON, already referred to, regarding the mosquitoes' that occur in the Colony of Hongkong.

Attached are the reports of :-

1. The Medical Officer to the Lunatic Asylums.

2. The Medical Officer in charge of the Public Mortuary.

3. The Medical Officer in charge of the Infectious Diseases Hospital.

4. The Medical Officer to Victoria Gaol.

5. The Medical Officer to the Tung Wah Hospital.

6. The working of the Medical Department in the New Territory during 1901.

7. The Report of the Government Analyst.

In conclusion my thanks are due to the several members of the staff for their assistance rendered during the past year, and I take this opportunity of thanking all those who in the past year have remembered the patients by forwarding them flowers, books, periodicals, &c.

I have the honour to be,

Sir,

Your most obedient Servant,

J. M. ATKINSON, M.B. (Lond.) D.P.H. (Cant.) Principal Civil Medical Officer.

The Honourable

THE COLONAL SECRETARY,

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$c.

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