736 



THE NATIONAL GEOGRAPHIC MAGAZINE 



similar disease on the Fiji Islands is con- 

 veyed by the same insect. Pink eye in 

 the southern United States is carried by 

 minute flies of the genus Hippelates. The 

 house fly has been shown to be a minor 

 factor in the spread of tuberculosis. The 

 bedbug has been connected with the dis- 

 semination of several diseases. Certain 

 biting flies carry the sleeping sickness in 

 Africa. A number of dangerous diseases 

 of domestic animals are conveyed by- 

 insects. 



The literature of the whole subject has 

 grown enormously during the past few 

 vears, and the economic loss to the hu- 

 man species through these insects is tre- 

 mendous. At the same time, this loss is 

 entirely unnecessary; the diseases in 

 question can be controlled, and the sup- 

 pression of the conveying insects, so ab- 

 solutely vital with certain of these dis- 

 eases and so important in the others, can 

 be brought about. 



MONEY LOSS CAUSED BY MOSQUITOES 



Entirely aside from the loss occasioned 

 by mosquitoes as carriers of specific dis- 

 eases, their abundance brings about a 

 great monetary loss in other ways. 



Possibly the greatest of these losses is 

 in the reduced value of real estate in 

 mosquito-infested regions, since these in- 

 sects render absolutely uninhabitable 

 large areas of land available for suburban 

 homes, for summer resorts, for manu- 

 facturing purposes, and for agricultural 

 pursuits. The money loss becomes most 

 apparent in the vicinity of large centers 

 of population. The mosquito-breeding 

 areas in the vicinity of New York City, 

 for example, have prevented the growth 

 of paying industries of various kinds and 

 have hindered the proper development of 

 la*-ge regions to an amount which it is 

 difficult to estimate in dollars and cents 

 and which is almost inconceivable. The 

 same may be said for other large cities 

 near the seacoast, and even of those in- 

 land in low-lying regions. The develop- 

 ment of the whole State of New Jersey 

 has been held back by the mosquito 

 plague. 



Agricultural regions have suffered 



from this cause. In portions of the 

 Northwestern States it has been neces- 

 sary to cover the work horses in the field 

 with sheets during the day. In the Gulf 

 region of Texas at times the market 

 value of live stock is greatly reduced by 

 the abundance of these insects. In por- 

 tions of southern New Jersey there are 

 lands eminently adapted to the dairying 

 industry, and the markets of New York, 

 Philadelphia, and the large New Jersey 

 cities are at hand. In these localities herd's 

 of cattle have been repeatedly established, 

 but the attacks by swarms of mosquitoes 

 have reduced the yield of milk to such an 

 extent as to make the animals unprofit- 

 able, and dairying has been abandoned 

 for less remunerative occupations. The 

 condition of the thoroughbred race horses 

 at the great racing center, Sheepshead 

 Bay, Long Island, was so impaired by 

 the attacks of mosquitoes as to induce 

 those interested to spend many thousands 

 of dollars a few years ago in an effort to 

 abate the pest. 



All over the United States, for these 

 insects, and for the house fly as well, it 

 has become necessary at great expense to 

 screen habitations. The cost of screen- 

 ing alone must surely exceed ten millions 

 of dollars per annum. 



MALARIA IS STILL SPREADING OVER THE 

 COUNTRY 



The west coast of Africa, portions of 

 India, and man}' other tropical regions 

 have always, at least down to the present 

 period, been practically uninhabitable by 

 civilized man, owing to the presence of 

 pernicious malaria. The industrial and 

 agricultural development of Italy has 

 been hindered to an incalculable degree 

 by the prevalence of malaria in the south- 

 ern half of the Italian peninsula, as well 

 as in the valley of the Po and elsewhere. 

 The introduction and spread of malaria 

 in Greece is stated by Ronald Ross, and 

 with strong reasons, to have been largely 

 responsible for the progressive physical 

 degeneration of one of the strongest races 

 of the earth. 



In the United States, malaria, if not 

 endemic, was early introduced. The 



