Mosquito Prophylaxis. ACh 
PREVENTATIVE MBrAsuRES. 
Preventative measures ona large scale, of course, can be undertaken only by 
the Government and Municipal authorities, and can be briefly summatised 
as follows :— 
(a) Systematic inspection of yards for breeding-places. 
(6) Vat-screening measures carried out effectively. 
(c) Keeping of trenches and waterways clear of vegetation and stocked 
with fish. These latter should be protected by prohibiting the catching 
of fish in trenches, etc. 
(d) Attention to drainage, by concreting, keeping all drains in good 
order and seeing that they ate nob choked so that puddles remain in 
places. 
(e) Education of the young and old as to the vital nevessity of helping 
the authorities in their work of mosquito destruction. 
(f) Penalties for harbouring larve or potential breeding-places on premises. 
Pusuic OPINION. 
With reference to these measures may I quote to you a short abstract from 
Sir Rubert Buyce’s book, “‘ Mosquito or Man,” a book I strongly recommend 
you to read, as many of his remarks are based on observations made during 
his stay in British Guiana. 
He says :—“ As part of any mosquito campaign, the education of public 
opinion must take a prominent share. In my experience in the tropics, I can 
state that the public is being educated to appreciate the danger of mosquitoes 
and other insect pests, and therefore to organise to get rid of them 
Pupil teachers, police officers, and those who wish to qualify for sanitary in- 
spectorships, are now being trained in mosquito destruction . . . But as is 
well-known, education is very well in its way, but unless it is occasionally 
backed up by the strong arm of the law, little progress would, in the long run, 
be made. It is now, at any rate in the West Indian colonies, becoming the 
rule to inflict penalties if, after due warning from the sanitary mspectors, the 
people will not get rid of stagnant water, or water m which larve are found. 
The beneficial effect of this salutary punishment is beginning to tell, and will 
in time completely change the health conditions . . . It is most satisfac- 
tory to record that, in spite of its novelty, the law is not resented, all classes see the 
wisdom of the measure.” 
Tam often asked: “Why is it that mosquitoes are so bad when rain 
falls after the dry seasun ?”’ The explanation is simple ; durmg the dry season 
many ponds and shallow trenches are completely dried up so that the larve 
and pup cannot live. This drying up process also kills out the many small 
fish that are the natural enemies of mosquito larve. But it does not kill 
the eggs which have been laid in the water by the female mosquito, some 
varieties of these eggs are provided with a thick, highly resistant shell, and can 
stand dessication for many months uninjured. Now when the first rain falls 
enough water is supplied to allow these eggs to hatch out into larve, but 
unless these pools are connected with a main trench no fish are present to 
devour them, therefore the larve develop into pupe and utimately itu 
