322 MOSQUITOES OF NORTH AMERICA 



cultivated. Then also, in further example, in quite recent years malaria entered 

 and devastated the islands of Mauritius and Eeunion, practically destroying for 

 a time the productiveness of these rich colonies of Great Britain and France. 



" Creighton, in his article on malaria in the Encyclopaedia Britannica, states 

 that this disease ' has been estimated to produce one-half of the entire mortality 

 of the human race ; and inasmuch as it is the most frequent cause of sickness 

 and death in those parts of the globe that are most densely populated, the esti- 

 mate may be taken as at least rhetorically correct.' 



" Is it possible to make any close estimate of the ratio between the number of 

 deaths from malaria and the number of cases of the same malady? No per- 

 fectly sound basis for such an estimate is apparent. In the English translation 

 of Celli's work on ' Malaria According to the New Researches,' published in 

 London in 1900, it is stated that the mortality from malaria in Italy from 1887 

 to 1898 varied from 21,033 in the first-named year to 11,378 in the last-named 

 year, and the mean mortality for the period is assumed to be about 15,000. In 

 1896 a count of the patients in the hospitals in Eome was made, and the mor- 

 tality rate of 7.75 per thousand of the actual patients was established. Calculat- 

 ing then on this basis, and at this rate, the number of cases per year for Italy was 

 placed at about 2,000,000. According to this estimate, and with the average 

 mortality for the United States of 12,000 as above indicated, the approximate 

 number of cases for the United States would be about 1,550,000. It seems 

 obvious, however, that Celli, in using the basis of hospital patients only, must 

 have underestimated the number of cases for the Kingdom, since of the people in 

 the country suffering from malaria the proportion entering the hospital must be 

 relatively small. Therefore the death rate from malaria of malarial patients 

 in the hospital must be greater than the death rate from malaria of the people 

 who suffer from this disease in the whole country. In fact, so great must this 

 discrepancy necessarily be that it would not seem at all unlikely to the writer 

 if the number of persons suffering from malaria in Italy were in reality nearer 

 3,000,000 than 2,000,000. 



" The same argument will hold for the United States, and more especially so 

 since as a rule malaria in this country is of a lighter type than in Italy ; in fact 

 an estimate of 3,000,000 cases of malaria in the United States annually is prob- 

 ably by no means too high. It will not be an exaggeration to estimate that one- 

 fourth of the productive capacity of an individual suffering with an average case 

 of malaria is lost. Accepting this as a basis, and including the loss through 

 death, the cost of medicines, the losses to enterprises in malarious regions 

 through the difficulty of securing competent labor, and other factors, it is safe 

 to place the annual loss to the United States from malarial disease under present 

 conditions at not less than one hundred millions of dollars. Celli has shown that 

 in Italy the great railway industries, for example, feel the effect of malaria 

 greatly. According to accurate calculations one company alone, for 1400 kilo- 

 meters of railway and for 6416 workmen in malarious zones, spends on account 

 of malaria 1,050,000 francs a year. The same writer states that the army in 

 Italy from 1877 to 1897 had more than 300,000 cases of malaria. 



" The loss to this country in the way of retardation of the development of cer- 

 tain regions, owing to the presence of malaria, is extremely great. Certain 

 territory containing most fertile soil and capable of the highest agricultural 

 productiveness is practically abandoned. With the introduction of proper 

 drainage measures and antimosquito work of other character, millions of acres 

 of untold capacity could be released from the scourge at a comparatively slight 

 expenditure. These regions in the absence of malaria would have added millions 

 upon millions to the wealth of the country. Drainage measures are now being 

 initiated by the United States. Parties of engineers are being sent by the 



