In the following remarks, however, it is not proposed to deal with the question of prevention on a large and public scale, but only with such as can be adopted as measures of individual and personal hygiene, as the larger question of provincial and municipal anti-malarial sanitation cannot be adequately dealt with in a short treatise like the present. Keeping always in view the just described data of the life history of the malarial parasite and of its temporary host, the mosquito, it is obvious that our measures of protection must be based on one or more of the following plans of action, any one of which, could it be carried to complete success, would suffice to “stamp out” the disease. These measures are:-- (1) To destroy the mosquitoes. (2) To prevent mosquitoes biting man. (3) To prevent mosquitoes from becoming infected, by isolating all cases of malaria in man. In practice, however, it is extremely rare that anything like complete success can be attained on either of the three above indicated lines of action, especially as concerns the second and third methods, and though here and there localities may be met with in which the breeding places for mosquitoes are so circumscribed and easily dealt with as to render the actual extermination of mosquitoes practicable, in by far the majority of cases we must be content with a partial success all along the line, by adopting such measures as may be locally most practicable, based on any or all three of the above principles of action. In the case, for example, of habitations placed in the midst of canal irrigation where ample and efficient subsoil drainage is impossible or too expensive, the attempt to destroy mosquitoes can be little better than a waste of time and money; for under such conditions the breeding places are so numerous, and appear so constantly in new and unexpected situations, as to defeat the utmost vigilance; and the thorough protection of all habitations against the invasion of mosquitoes, and the careful treatment of all cases with quinine, is all that can be done. On the other hand, in an exceptional case, such as that of the town of Ismailia in Egypt, where the rainfall is practically _nil_, and the breeding places all of artificial origin, the practical extermination of mosquitoes may be so easy a matter as to be effected at a small expense in a single year, with the immediate result of reducing the cases of malaria to a tithe of their previous numbers. Measures of the first class, _i.e._, the extermination or diminution of the numbers of mosquitoes, can often be undertaken with considerable success by private individuals, the possibilities of success varying, of course, with the extent of the area directly or indirectly under his control.