It is generally agreed that the most important advance of last year in the science of medicine was the discovery that the parasite causing malaria was transmitted from person to person by mosquitoes. Dr. Manson describes this discovery fully in this number of the POPULAR SCIENCE MONTHLY. This summer a crucial experiment is being made of a somewhat dramatic character. A mosquito-proof tent has been constructed, which is located in Italy, in the Campagna. In this Dr. Luigi Sambon, lecturer of the London Tropical School of Medicine, and Dr. G. C. Low will live until October, taking the utmost care not to be bitten by mosquitoes. If they escape malaria it will serve as corroborative evidence that the mosquito is the means of infection. On the other hand, several Englishmen, including Dr. Manson’s son, have offered themselves as subjects for the complementary experiment. They will live in a healthy district, but will definitely allow themselves to be bitten by mosquitoes which are known to be infected. These experiments will probably be particularly useful in demonstrating to the public at large the validity of the hypothesis derived last year from technical bacteriological evidence. Transcribers’ Notes Punctuation, hyphenation, and spelling were made consistent when a predominant preference was found in this book; otherwise they were not changed. Inconsistent spacing in abbreviations was not changed. Simple typographical errors were corrected; occasional unbalanced quotation marks retained. Ambiguous hyphens at the ends of lines were retained. Page 230: “spectrograph” was misprinted as “spectograph”; corrected here. Page 315: “sporozooites” was printed that way. Page 322: “uranium oxids” was printed that way. Page 329: “‘Plant Geography of North American,’” may be a misprint for “America”. End of Project Gutenberg's The Popular Science Monthly, July, 1900, by Various