364 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 10 



and sending tributary streams to these two great rivers be divided by 

 a line from the Suisun Bay to Mokelumne Peak it will be found that 

 eleven counties to the north of this line show 50 per cent of the deaths 

 from malaria in 1909, and thirteen counties to the south of the line 

 show 30 per cent of the deaths from this cause. In other words, the 

 Sacramento and San Joaquin valleys contributed 80 per cent of all the 

 deaths from malaria within these valleys. The following figures are 

 significant: Nine of the twenty -four counties had 75 per cent of the 

 deaths, or 60.6 per cent of the deaths for the entire state. These nine 

 counties fall into three groups, (1) Placer, Sacramento, San Joaquin, 

 with 25 per cent of the deaths and a population of 136,774; (2) Butte, 

 Tehama, Shasta, with 24 per cent of deaths and a population of 57,622; 

 (3) Fresno, Tulare, Kern, with 11.6 per cent of deaths and 148,812 

 population. 



"Reducing these figures to terms of 100,000 population and com- 

 paring with the United States census average of 4.8 for the entire reg- 

 istration area, "the Butte-Tehama-Shasta area shows 46.8 deaths per 

 100,000 population; the Placer-Sacramento-San Joaquin area shows 

 20.4 deaths per 100,000; and the Fresno-Tulare-Kern area shows 8.9 

 deaths per 100,000 population." 



The above report on malaria conditions in California is not based 

 on endemic indexes and has consequently been regarded by some as of 

 comparatively little value. While the writer had not undertaken a 

 systematic study of large numbers of blood smears, enough of these 

 had been examined both prior to and after Snow's report that he is 

 convinced that endemic indexes would have shown the statements 

 above quoted practically correct. As it is, control work already ac- 

 complished would alter the situation. 



Meyer^ states "We examined the blood of 272 children in Gridley 

 (Butte County) and of 364 children in Chico (Butte County) and 

 found a tertian infection in each place (one seventeen-year-old Japa- 

 nese boy in Gridley and one nine-year-old girl in Chico)." This could 

 not well be regarded as a representative index, the work having been 

 done early in the season (May 17-31, 1915) and included only a por- 

 tion of the school children. A very much more significant index was 

 made by Kelley^ at Redding (Shasta County) where an index was 

 made in October, 1915, based on 435 blood smears taken from as 

 many school children showed thirty-five infected or an index of 8 per 

 cent, there being 17 cases of aestivo-autumnal, 17 cases of tertian and 



1 Meyer, Karl F. The Malaria Problem. Trans, of the Commonwealth Club of 

 California, vol. XI, No. 1, pp. 21-26 (March, 1916). 



2 Kelley, Frank L. Endemic Index of Malaria in the Northern Sacramento Valley. 

 Joum. of the Amer. Med. Assoc. (In press). 



