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fumigation with sulphur or pyrethrum 

 powder. This, however, is an incomplete 

 way, and since the Anopheles breeds 

 by preference in small puddles and shal- 

 low stretches of weedy swamp or slowly 

 moving water free from small fish, its de- 

 struction is rather an engineering than a 

 medical question. Much may be done by 

 pouring kerosene and paraffin on the 

 surface in the proportion of about 

 a tablespoonful to every square yard 

 of surface, so as to form a thin film, which 

 clogs the air tubes of the larvae and 

 pupae, and also kills the adult female 

 while depositing eggs. This remedy will 

 be found efficient by those of you who 

 are worried by the local Culices, which 

 evince a bloodthirsty disposition in New- 

 town, at any rate. Culices are especially 

 fond of small collections of water in pots 

 and tanks— the saucer of a flowerpot on a 

 window sill may provide sufficient mos- 

 quitoes to make the inmates' life a misery, 

 while an ordinary 400 gallon tank will stock 

 a neighborhood. 



The moral of which, as Captain Cuttle 

 is recorded to have remarked, lies 

 in the application thereof. I need not 

 say more than that the notoriously 

 malarious localities of Sierra Leone 

 and Freetown, formerly known as the 

 " white man's grave " in West Africa, 

 have, comparatively speaking, been turned 

 into health resorts within two years of 

 organised effort against mosquitoes, and 

 that at Ismailia, in Egypt, a previously 

 notoriously malarial town, the average 

 number of cases has been reduced from 

 2000 to 200 per annum by one season's 

 work. Practically, there were no fresh 

 cases of malaria once the work was got 

 going, and it is now possible to sleep there 

 n safety without a mosquito net, probably 

 for the first time in the history of the town. 

 Probably everyone here to-night has been 

 at one time or another subjected, un- 

 asked, to the gastronomic attentions of a 

 female mosquito, and the method in which 

 she performs the operation after a pre- 

 liminary song may be a more or less in- 

 teresting memory on the next occasion you 

 commit culicide. (The lecturer here de- 

 scribed with a lantern diagram the 

 manner in which the mosquito feeds). 



So far we have considered the cor- 

 poreal life of the malarial organism, 

 that is, the part of its life-cycle which 

 is passed in the blood of man, with 



the single exception of that octopus-like 

 male gamete which, as I pointed out, only 

 developes after leaving the human body. 

 Turning now to the second, or extra-corpo- 

 real stage of its life history — i.e., that stage 

 which, as we now know, is passed in the 

 mosquito — we find that there are really 

 two forms of cell developed amongst the 

 organisms, one the octopus-like male 

 gamete, the other a spherical cell. 

 Now, it is only when the Anopheles takes 

 in blood containing parasites at, or about 

 this particular stage of development, that 

 it becomes infected with malaria, and 

 capable of conveying it to fresh human 

 beings, a fact which accentuates the im- 

 portance of protecting malarial patients 

 by means of mosquito nets wherever 

 possible. Having taken in the blood, 

 however, by means of the complicated 

 sucking apparatus, which I have de- 

 scribed, the gametes develop into the 

 sexual form, and the true function of 

 the male's loose arm becomes evident 

 since it joins with a spherical cell formed 

 by another gamete, and impregnates it. 

 It was the female gamete which it was in 

 search of when it cast loose. Then the fer- 

 tilised cell or zygote attaches itself to the 

 stomach wall of the mosquito, bores its 

 way through, grows greatly in size, and pro- 

 ceeds to divide into a great number of 

 tiny cells. It becomes a cyst, which 

 finally bursts and sets free the tiny 

 structures within, which have meanwhile 

 developed, and these, set free in the body 

 cavity, settle in great part in the veneno- 

 salivary gland at the base of the pro- 

 boscis, as tiny thread-like bodies, termed 

 zygotoblasts or sporozoits. The gland 

 in which they lie is that which 

 secretes the irritating substance of 

 which we all know the effects in con- 

 nection with a mosquito bite, and ia 

 the case of an infected Anopheles, they 

 are injected with this secretion along the 

 proboscis. The process for their de- 

 velopment in the mosquito takes about 12 

 days from the date of the meal of infected 

 blood, before the thread like bodies 

 appear in the gland. After injection, along 

 with the secretion, the sporozoits infect the 

 blood corpuscles, grow rapidly, and break 

 up into spores which in time infect fresh 

 corpuscles, until a huge swarm of para- 

 sites, with a life cycle of either 48 or 72 

 hours is produced in the blood. The 

 breaking-up of each swarm sets free 



