oi. osts. — The destruction of 141 organism is effected partly do.? proccss of pliagocytosis and -rtiv bv the germicidal properties of imioil-plasina, but the relative int : ..rt. et. plavtd by each is not, as yet, t..t;ri• v eltar. That the blood-plasma mar pts,css this. effect is well demon bv the destruction of the young :pi ris after the exhibition of quinine. '1 1 t etlls chiefly concerned in phago evii are the large mononuclear and vinorphonuclear leucocytes and cells d. r.‘td from the spleen, liver, and bone n- Arrow. termed macrophages, as well as fr,m the endothelinin of the blood-vessel ,ads. The process is to be best observed .1 V the microscopical examination of the r:an,.. after death, although during life it mav be satisfactorily studied in blood w;thdrawn from the spleen and, to a :iii-itecl extent, in the peripheral blood. TI e phagocytes may attack the organism whil, it is contained within the red 1 lood-corpuscle and envelop both host and parasite. The flagellate bodies ap r_lr to be objects of particular attack, '.,gethor \vith extracorpuscular and vari ,m3 other degenerated forms. As just .ncil-ated. however. to the blood-plasma to be ascribed an important part in the .iniction of the parasites. This is con rrn,fd by the fact that the greatest de -rniction of the parasites occurs at the •:rne sporulation, when the young an.,.-rn is set free in the plasma, and bv the further fact that it is at this period the cycle of development that quinine pxerciFeF its greatest influence. We may conclude, therefore, that the destruction rf the parasite is affected by the com ' action of the blood-plasma and the phagocytes.
Tile lymphocytes are never phagocytic in malaria. Those holding the opposite VieW have been misled by the fact that normally there exists a lymphoeytic pig mentation which is, therefore, a physi ological not a pathological condition. Patrick Manson (Brit. Med. Jour., Sept. 24, '98).
— Since the discovery of the malarial parasite much work has been done looking to a solu tion of the problem of the manner in which infection of the body takes place and the channels through which the or csanism enters. This is one of the most important of the, as yet, unsolved prob lems relating to malaria, and until its solution is attained an effective prophy laxis cannot be hoped for.
It is agreed that infection may pos sibly take place by the entrance of the parasite through:— 1. The digestive tract (the \vater theory).
2. The respiratory tract (the air theory).
3. The skin (the inoculation-theory).
1. Although many believe that mala ria may be conveyed into the system through the digestive tract by means of infected water, the weight of evidence is overwhelmingly against the probabil ity that infection occurs by this channel. To prove it the experiment, to he con clusive, must be made upon a person who has had no previous exposure to malaria and who at the time must be removed from any other possible malarial influ ences, and after the administration of the supposedly-infected water the blood must be properly examined for the pres ence of the parasite.
[Celli (quoted by Mannaberg: Noth nagel's Spec. Path. u. Ther., B. 2. T. 2, S. 94), in the Hospital of S. Spirito, Rome, caused several persons to drink water derived from the pontine marshes and from the marshes in the regions surrounding Rome, for a number of days, and none of them developed malaria. Brancaleone (quoted by Mannaberg: Notbnagel's Spec. Path. u. Then, B. 2, T. 2, S. 94) pursued the same experi ment in Sicily with the same nega tive result. Zeri (quoted by Manna berg: Nothnagel's Spec. Path. u. Ther., B. 2, T. 2, S. 94) caused nine persons to drink water derived from a malarious region for from five to twenty days; the dust derived from the evaporation of water from the same source Ile caused to be inhaled by sixteen persons; and to five persons he gave rectal injections of the infected water. None of the persons thus experimented with developed ma laria. Norton (Johns Hopkins Hosp. Bull., Mar., '97), in a recent review of the subject, states emphatically that in his opinion malaria is not a water-borne disease. JAMES C. and THomAs G. AsirToN.] If the transmission of rnalaria is aiIrial only, there are certain localities close to sources of malaria the freedom of which from infection cannot be explained. Transmission by drinking-water eon , sidered as more probable. Malarious countries have been traversed with im , punity by drinking only boiled water, while villages have witnessed the disap • pearance of fever as the result of a supply of pure water. Experiments of Marino, Leri, and Baccelli quoted, how ever, to show that the theory of water , borne malaria is not altogether tenable.
Laveran (Presse MM., Jan. 20, '97).
2. The view that the malarial parasite may enter the system by way of the respiratory tract is still entertained by many, who, in support of their belief, instance the supposed influence of the winds in conveying the infection. The evidence is decisive, however, that, al though the winds may carry the malarial organism, the distance through which this is probable is a very limited one. Numerous instances are on record of the anchorage of ships a very short distance off the coast of highly-malarious districts without any members of the crew, pro vided they do not land, contracting the disease. On the other hand, should members of such ship's crews land, in fection almost invariably follows. Again, in many instances the moderate elevation of a residence, although surrounded by malarious swamps, will often prove ef fective in preventing infection; and it is well known that in a malarious district persons residing upon the ground-floor of a dwelling may become infected, while those residing in the upper stories will escape. Further, it is well recognized that the line of separation of certain malarious localities from the surround ing healthy region is, for some obscure reason, sharply defined: a circumstance which could not occur were the malarial parasite suspended in the atmosphere in such a way to be taken into the respira tory tract.