238 MOSQUITOES OF NORTH AMERICA 
“WrrExLy Reports oF DISEASES IN MICHIGAN. 
“ PER CENT. OF REPORTS WHICH SHOWED INTERMITTENT FEVER. 
OTST Giws3 eats 15% 1891....... 36% 1898 
1878....... 82 1892. . 27 1899... 
1879....... 82 1893.. . 24 1900... 
1880....... 82 1894....... 24 1901 
1881....... 82 1895....... 22 
1882....... 71 1896....... 19 
1883....... 69 1897....... 17 
“Tn 1879, 1880 and 1881, intermittent fever was the most prevalent of all 
diseases in Michigan; in 1881 the western division of the State, including the 
locality described above, showed a greater prevalence of malaria than other 
parts of the State, 90 per cent. of all weekly reports recording the disease as 
under the observation of the physician making the report. But according to the 
statements of local physicians the disease has been very infrequent in and about 
Eastmanville for the last few years. One physician had observed during six 
years but three cases presenting a typical malarial history ; one of these occurred 
in the summer of 1889, one in 1902, and one in 1904. All three patients lived 
on the bank of the river, at distances of several miles from one another. 
“The question of course arises whether this decrease in malaria has been 
paralleled by a decrease in the number of the malaria-carrying mosquitoes. In 
the absence of data, no definite statement can be made regarding the number and 
virulence of mosquitoes in the earlier years of the settlement, except the very 
general one that they were much ‘more numerous’ than at present, and that 
they were very large. They were felt as so real a pest that the farmers would 
often leave the unscreened houses to sleep in the barns and haylofts, which were 
not frequented by mosquitoes.” 
The effect of drainage as a corrective of malaria was naturally noticed long 
before the fact that Anopheles is the carrier of the disease was discovered, and 
in the earlier works a number of such instances have been pointed out. We have 
already referred to the extensive drainage of the fens in England, and of course 
the sanitary benefit arising from this drainage was at once perceived. In his 
excellent work on malaria and malarious diseases (New York, 1884), Sternberg 
refers to the case of Boufaric in Algeria which was noted for its unhealthiness. 
Successive importations of soldiers and colonists died off from malaria. Deep 
drainage was resorted to, and the level of the ground-water was lowered less than 
two feet. Too this measure was attributed the reduction of the mortality to about 
one-third. He points out that the completion of the system of drainage in the 
towns of Fairfield and New Milford, Connecticut, resulted in the steady and 
rapid decrease of malarial diseases. He further shows that, according to Colin, 
while the laborers engaged in drainage measures often suffer very severely from 
malaria, the subsequent effect is to greatly increase the health of the locality. 
He cites the instance of Staouéli in Algeria, where the reclamation by drainage 
of the lands belonging to a Trappist convent cost, during the first years, the lives 
of eight monks out of twenty-eight and of 27 soldiers out of 150 who were placed 
at their disposal. The improvement in the health following the drainage, how- 
ever, was very great, and in eighteen months there were but two deaths out of 
a population of 152. 
