Page:Popular Science Monthly Volume 81.djvu/53

Rh, the number of deaths from malaria in Habana was greatly reduced from 325 in 1900 to 151 in 1901, 77 in 1902, and 45 up to the first of November, 1903.

In 1905, yellow fever broke out in New Orleans. The situation was critical, and on August 12 was placed under the control of the Public Health and Marine-Hospital Service under Dr. White. A warfare against the yellow-fever mosquito was at once commenced. This mosquito was found breeding in the rain-water cisterns which abounded in the city. These cisterns were screened, and various pools treated. The epidemic abated at once, and the total number of deaths was 460 as against 4,046 in the epidemic of 1878, 4,858 in 1858, and 7,848 in 1853.

Similar control measures have been inaugurated in the Panama Canal zone, with the result that the canal is soon to be completed and the region is now considered fairly salubrious, though the French had to abandon their work there on account of the unhealthy climate.

Mosquito prophylaxis is usually an engineering problem pure and simple—abolish breeding places. This can be done in nine out of ten cases by filling and draining at small expense. In the tenth case it may be advisable, on account of expense, to make a permanent pool and stock it with carnivorous fishes. The edges should be deep and abrupt, and kept clean and free from vegetation. In the salt marshes, ditches should be opened so that the tide may ebb and flow through them, and mosquitoes will not breed there. Fill all small depressions.

Screen all houses, and also screen all cisterns and rain-water barrels to keep mosquitoes out of them. Treat the surface of all breeding places once each ten days with oil to prevent the breeding of mosquitoes therein until these pools can be made permanently safe.

Bubonic plague, or "black death," has always been one of the most dreaded diseases of mankind, and from the scourge of Egypt, beginning about A.D. 542 and lasting sixty years, down to the San Francisco epidemic of 1907-08, communities and government authorities have been powerless to cope with it. In India even at present, according to the newspapers, the mortality from this disease was 43,508 for the month of February and 95,884 for March, 1911. As it has always been serious in India, various commissions there and in other countries have each investigated and made their own contributions toward a knowledge of the disease. From 1896 to 1903, during these investigations, it was learned that the bacterial germ Bacillus pestis, causing the disease, entered through some wound, puncture or abrasion of the skin, and that all fleas and bugs sucking the blood of dying plague-diseased