30 MOSQUITO WOKE IN KHARTOUM, ETC.

Regulations for the prevention of malaria generally

A ‘ ‘ mosquito plant”

No. Strength of Solution.

5b 1 in 50,000

6a 1 in 30,000 Do.

6b 1 in 30,000

8

1 in 10,000? some suspended

matter.

1 in 1,000 ? much deposit.

Eesult. Temp, of Water. Larvae of Pyretophorus costalis all alive 28*5°C

after 48 hours. A few alive after 72 hours and after 96 hours. Pupae formed. Discontinued. Culex fatigans. Nearly all the larvae

dead within 40 hours. Some alive after 72 hours. All dead within

4 days. Larvae and pupae of Culex fatigans and

Pyretophorus costalis. Very sluggish in 20 hours. Some dead. Some alive at the end of 24 hours. All dead except one larva and one pupa of

Culex fatigans within 44 hours. All dead in about 50 hours. Killed larvae of Culex fatigans within

18 hours, not in 5 hours.

Do.

Do.

Do. Killed advanced larvae of Culex fatigans

in 25 minutes. All the larvae and pupae killed were stained a bright yellow. The solutions soon altered a little in strength owing to evaporation, and, as will be seen, the results were somewhat indefinite.

Mosquito work has not, however, been confined to Khartoum. At the request of the S.M.O. Khartoum one drew up a set of simple regulations, with reference to the prevention of malaria, for the use of outlying stations. It was

on the lines of Major Ross’s recommendations, and in addition, care was taken to include those measures rendered necessary by the discovery, made by those 1

who have worked with forest mosquitoes, of breeding places in pitcher plants and hollow trees holding water.

From Kassala, Captain Ensor reports a great improvement both as regards mosquitoes and other noxious and annoying insects which pass their larval stages in water. In this connection, it is interesting to note that the Shilluks have a so-called “mosquito plant.” They dry the leaves and lay them inside the roofs of their huts. The myth of the basil,2 if not that of the neem, has been exploded, so that probably this precautionary measure is of no value. I have

not been able to obtain a specimen of the plant.

Mr. Cross brought the laboratories specimens of Mansonia uniformis from Renk, and Dr. Christopherson sent certain mosquitoes he collected up the Blue Nile. Unfortunately, these had not been mounted and were much damaged. The fact

1 Lutz. Cent. f. Bakt., &c. Bd. xxxiii., No. 4, Jan. 1903. Leicester. Journal of Tropical Medicine, 15/9/03

2 Prout’s Experiments. The Tirftes, London, 27/7/03