PROTECTIVE LIQUIDS 365 
SCREENING BREEDING-PLACES. 
What we have said in regard to the size of mesh to be used in window screens 
and canopies applies equally well to screens over possible breeding-places to 
prevent the breeding of mosquitoes or the issuing of mosquitoes which have bred 
therein. In cities like those in the Gulf States, where the rain-water supply is 
conserved in large tanks, screening is necessary and is now enforced, Galveston 
and New Orleans perhaps being the first to make this an important health 
measure. But rain-water barrels everywhere must also be screened in the same 
way, except where fish are used to kill the early stages of mosquitoes. In out- 
of-the-way places, however, where it is difficult to get good screens or where the 
expense of screening is seriously to be considered, a cheap cover may be made 
for well-mouths or water barrels, such as described by Dutton in his Report of 
the Malaria Expedition to the Gambia and which he states was devised by 
Doctor Forde. 
“This cover consists of a large iron hoop obtained from discarded barrels, 
to which is fastened all round a piece of stout calico or sacking free from holes, 
in such a manner that a good deal of sag is left in the material. After water is 
obtained from the well the hoop is thrown over the mouth, and the calico 
catching on the rim of the well completely closes the entrance and is kept taut 
by the weight of the iron hoop. This cover is so simple, and, however carelessly 
applied, must so effectually close the entrance of the tub against mosquitoes, 
that I think it is well worthy of extensive use in the town. Dr. Forde has lately 
informed me that these covers are now being made in Bathurst, and are sold to 
the natives for the sum of four pence.” 
PROTECTIVE LIQUIDS. 
A number of different substances have been in use to rub upon the skin or to 
put near the bed as a protection from mosquitoes. Spirits of camphor rubbed 
upon the face and hands, or a few drops on the pillow at night will keep away 
mosquitoes for a time, and this is also a well-known property of oil of penny- 
royal. The use of oil of peppermint, lemon juice and vinegar have all been 
recommended for use as protectors against mosquitoes, while oil of tar has also 
been used in bad mosquito localities. A mixture recommended by Mr. E. H. 
Gane, of New York, is: 
Castor oil 1 oz. 
Alcohol 1 oz. 
Oil of lavender 1 oz. 
The oil of citronella has come into very general use in the United States in 
the past few years. The odor is objectionable to some people but not to many 
and it is efficacious in keeping away mosquitoes for several hours. A mixture 
recommended by Mr. C. A. Nash, of New York, composed of 
1 oz. oil of citronella 
1 oz. spirits of camphor 
4 oz. oil of cedar 
has been the most efficacious mixture tried by the writer. Ordinarily a few 
drops on a bath towel hung over the head of the bed will keep Culex pipiens 
away for a whole night. Where mosquitoes are very persistent, however, a few 
