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going on among the troops at Wilberforce; and the same thing may obviously often happen in private houses.

24. F.-General use of Mosquito-nets and Punkahs.- In India, where guat-fever is comparatively common among natives and the poorer Europeans, it is exceptional among the well-to-do Europeans. We are inclined to attribute this to the general use among the latter of mosquito-nets or punkahs during sleep-a usage founded on the experience of many generations. We are struck by the fact that in this Colony these comforts-they may rightly be called necessities--are not employed so generally as they should be, and we are disposed to ascribe the great mortality among Europeans here largely to this cause.

25. Commodious square nets of the Indian pattern, if free from rents and stretched between poles and the mattress, exclude mosquitoes, and at the same time allow the free passage of air; and there can be little real objection to their use on the ground that they increase the heat, especially as the nights are comparatively cool here. But it should be remarked that many persons use their nets-when they do use them-in so unintelligent a manner as they serve rather to retain the gnats than to exclude them.

26. G.-Houses for Europeans.— Again, in India, where long experience has taught Europeans how best to live in tropical climates, we observe that their houses are generally surrounded by a large open space-the "compound ”— and are placed on as high ground as possible. These rules are not observed here, where Europeans are often compelled to live in structures which are frequently ill-built, crowded together, separated from adjacent buildings only by evil-looking yards, and are situated on the very lowest, hottest, and dampest part of the town. This is the more surprising since excellent sites very close to the business parts of the town are to be found on the flanks and summits of the adjacent bills. The principle is already conceded by Government having placed the troops on these hills; and it seems hard that other Europeans should not enjoy the same advantages as military officers.

27. We should add, that we have found no anopheles in the barracks on Tower Hill and Mount Aureole, and that those found at Wilberforce appear to come from a very local source, which, it is hoped, may be ultimately discovered, The lowest parts of the town, namely, those in proximity to where many Europeans now live, are the principal haunts

of these insects.

REMARKS,

28. The above recommendations for the prevention of gnat-fever may be summarised as follows:-

(4.) The most permanent and satisfactory measure is the obliteration of the

breeding-pools of anopheles by drainage.

(b.) Failing this, the employment of an agent to destroy the larvae of anopheles and other gnats is likely to be very useful, provided that the agent performs his duty.

(c.) When the anopheles cannot be exterminated, wire-screens to the windows, and

mosquito-nets should be employed.

(d) Houses of Europeans should be built on elevated sites.

of

29. It scarcely needs to remark, that if these suggestions are to bear fruit they must be acted on in a fully intelligent manner by those appointed to the work. Thus anopheles puddles can be simply brushed out with a broom, while others can be cleared

many out with a few strokes of the spade. Creosote, or some oil more stable than kerosine oil, may possibly be used for permanently poisoning the larger puddles. Again, if drainage is to be employed, care should be taken not to waste funds by draining marshes and pools which, however suspicious they may look, do not and cannot contain anopheles larva. Moreover, it must be remembered that old pools may dry up and new ones be formed at different seasons. Lustly, it is most important that these observations be extended to other parts of the Colony-that anopheles pools be sought for in the more populous villages, and that the relations between epidemics of fever and gnats be followed with all care and knowledge, so far as possible. It would seem then, that all medical officers and others who may be connected with this work, should know how to distinguish gnats of the genus anopheles, and how to discover their breeding pools a subject with which some of

Your Excellency's medical officers are already fully acquainted.

30. Dr. Strachan, Chief Medical Officer at Lagos, has been kind enough to send us specimens of anopheles, which he says abound in that Colony. They are the same as the anopheles found.here. He adds, that their larvæ occur in pools of water on the ground. It would appear likely then, that these species of anopheles occur all down the coast, where they probably carry most of the fever which has long rendered this region so destructive of life,

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31. We have said that it is not yet certain whether other species of gnats cannot convey the infection, This point demands systematic and continued investigation.

32. Your Excellency has also done us the honour of inviting our opinion respecting the prevention of "serious cases of fever.” So far as such cases are truly malarial or gnat-fever, that is, fever due to the parisites known as the llamamırbide and carried by gnats, we have already offered our suggestions; but we are unable to say whether serious cases of fever due to quite other causes are not prevalent here. The routine use of the microscope in medical practice is the only means by which this question can be definitely

settled.

33. We beg to take the present opportunity of thanking Your Excellency for the assistance and encouragement which you have given to our investigations,

We have, &c.,

RONALD ROSS, D.Ph., M.R.C.S., Major F.M.S. (ret.)

H. E. ANNETT, M.D., D.Ph.

ERNEST E. AUSTEN, Brit. Mus, (Nat. Hist.)

R. FIELDING-Oct.ò, M.A., M.B.

Enclosure No. 2 in 267.

HONOURABLE COLONIAL SECRETARY,

I PRESUME that any remarks of mine must be of the nature of a criticism on any point in which it may seem to me that my longer experience of the West Coast of Africa may be of some valuie.

It is unnecessary for me to say that with the conclusion and recommendation of the Report generally I entirely agree.

As Major Ross points out, it may be taken as definitely proved that the infection by mosquitoes is one of the methods by which malaria can be contracted, and it may be also taken as proved, that a mosquito which has bitten a person suffering from malaria at a certain stage, is capable of infecting a healthy individual. On the other hand, I must confess that personally I am inclined to think that there are other methods by which malaria may be contractel, and I am also inclined to believe that it is probable that a certain species of mosquito may transmit nalaria from, say, the soil or pools direct, without having previously bitten a Healthy individual. The character of the pools in which the anopheles larvae breed seems to me to render it not impossible that the cause of malaria may be taken up directly by the larvae, grow in the adult, and be transmitted to man; this is further supported by the fact that the non-hurtful mosquito grows in pots, tins, &c., under entirely different conditions. When we remember that at certain seasons cases of fever are rare; that the disease can only grow in a mosquito, if it bites the individual at a certain stage of the attack, when the sexual form of the parasites are in the peripheral circulation; that after that, it requires seven or eight days before it is capable of transmitting infection; that then the period of incubation in the human being is probably from six to ten days, it seems to me, we have such a long eyele to complete that it is difficult to believe that infection from one individual to another can be the sole method of acquiring the disease.

All this is, however, mere theory, and these points want very careful working out. 3. But granting that the anopheles can produce fever, it is evident that we must try to get rid of it, and I am entirely in accordance with Major Ross that the "most satisfac- tory prevention of gnat-fever would be the obliteration by drainage of the breeding pools of anopheles." I need hardly remind His Excellency that this is a method which I have been recommending for years past, even though it was not based on the mosquito theory, but on our knowledge of what has been done in other places in the way of the prevention of malaria, and I would refer to my annual reports in support of this, "I would draw special attention to paragraph 12 of Major Ross's letter.

4. I must confess that I look upon any other method of dealing with this matter as merely tinkering with it, and I am convinced, that the question of the expenditure will have to be faced sooner or later. Of course, the drainage of huge tracts of country need not be contemplated, but that localities can be freed from malaria in this way has been proved over and over again. The drainage of many parts of Freetown (I am aware that I am speaking on an engineering matter, and I do so subject to correction) seems to me a comparatively simple matter.

5. The oil method appears to me worthy of trial, simply on the score of its slight expense, but if we recollect the possibility of overlooking a pool or two, the fact that one