THE CONTROL OF MALARIA.

Based on the facts that the diagnosis of malaria can be made by microscopic examination of the blood, and that the malarial parasites are destroyed by the proper, continued administration of quinin, Koch and his collaborators instituted a systematic campaign toward the complete eradication of malaria in several more or less well circumscribed districts. They assumed that the malarial parasites can live only in mosquitoes and human beings. If the truth of this assumption be accepted—and there is no reason to question it—it follows that it becomes possible to eradicate malaria in either one of at least two ways, namely, either by destroying the malaria-carrying mosquitoes, thus preventing the parasites from multiplying and infecting new patients, or by securing such control of the malarial patients in a given locality that all the parasites in their blood are destroyed by the prolonged use of quinin, thus again preventing further multiplication