372
presence of one or two adult servants that the danger lies, but in the numerous families (with children) crowded into dark and dirty huts so universally seen at the European's door. Once the fact is recognised that it is from the crowded cooly lines and native quarters that the European derives bis fever we feel sure that the whole hygienic aspect of these fever camps will change.
Segregation on Military and other Expeditions and for Travellers and Sportsmen.
The facts already put forward explain also why military expeditions in Africa are attended with such a large amount of sickness and so terrible a mortality. As an example of the mode of contracting malaria on military expeditions we may in-tance Prahsu, a well known halting place on the way to Kumasi from the Coast. It is probable that every man passing up or down to the Coast during the Ashanti campaigns slept at least a night at this station. From plans of the condition there, European quarters and native huts in close proximity, it is at once evident that here at least was one of the sources of the sickness and mortality among European troops, and not in the "climate."
In native villages the native porters are able to procure food, and here generally a clearing is found ready for a camp. So that it is the almost invariable practice of travellers of all kinds to camp in the village clearing, often to sleep in the native huts.
Here, again, we find the inevitable result. Although the traveller may not pay much attention to their bites, the Anopheles from the huts have injected malaria parasites (sporozoits) into his blood, and ten days later he is "down with fever."
Here, briefly, though it is a most important practical point, we must consider the question of flight of Anopheles. As the result of very numerous observations and experiments both in Africa and India we may emphatically state that Anopheles do not olten fly a quarter of a mile, and practically never half a mile. We e are considering. it must be understood, the habitual, not the possible maximum, flight. Anopheles, in fact, tend to leave but for a short distance the thatched huts in which they spend the day, and although we give a quarter of a unile as a maximum flight yet a segregation of 100 yards from a native but is infinitely better than none at all. Also, every natural obstacle tends to aid segregation, and should be taken advantage of, as the ridge of a hill,
hill, a belt of trees, bananas, bamboos, &c., and though a well isolated dwelling, with no native families within a quarter or half a mile, should be aimed at, yet when native huts exist which it is impossible to remove, they should be as completely screened as possible by the planting of bananas, &c.
To sum up these various conditions we may say that a European who pitches his camp or builds his permanent quarters half a mile, to take an extreme limit, from any collection of native huts, however small, will avoid infection otherwise almost inevit- able, and if in his compound he allows only those servants absolutely necessary, he is in a position to escape the dangers of life in tropical Africa.
PERSONAL PRECAUTIONS.
We cannot emphasize finally too strongly the need at present for these. We, ourselves, by unremitting care, completely escaped contracting malaria during over three years' residence in Africa and India; in places, too, where, more frequently than not, the deadly conditions we have described existed. Among these precautions we place the proper use of a mosquito net as by far and away the greatest means of individual protection.
1. Mosquito net. The net should be square (not a bell net), should not have a single, even minute, hole, should hang, inside the poles if these are used, should be tucked in under the mattress, and should not trail on the ground. A piece of closely woven material, fastened on all round at the level of the body is a necessary addition, in order to protect the limbs during sleep from bites through the net. When not in use the ends of the net should be twisted up somewhat, and then thrown over the top. We always arranged our nets ourselves, never trusting to servants, and further, to be doubly certain, we always carefully searched the interior with a candle before going to sleep. To these minute precautions, solely, we attribute our absolute freedom from malaria.