STATE HORTICULTURAL SOCIETY. 145 



it became the " cleanest city of its size in the world." The fever did not appear ; but 

 as this care was relaxed, and dirt again became the rule, fever has again made its 

 appearance. It is found that growing vegetation, especially trees, has a protecting 

 influence against malaria. It la stated that Lieut. Maury interposed several rows of 

 sun flowers between the National observatory and the malarial region of the Potomac, 

 with eminent success In diminishing the unheal thineas of the locality. La Roche, as 

 quoted by Blodgctt, says that "a thick forest formerly extended on the south side of 

 Rome, protecting it from the influence of the Pontine marshes ; this belt has been 

 reserved and the country has become proverbial for its unhcalthincss. Trees were 

 planted by the Romans to protect localities in this manner, and the practice was 

 enforced bylaw: " Whole families," says Bartlett, " have resided near the Pontine 

 marshes, and by the intervention of shrubs and trees have escaped for years the nox- 

 ious efTects of their putrid waters." Dr. Hosack states that "a family in New Jersey 

 was attacked with fever, in consequence of cutting down a wood that separated them 

 from a morass in the J e'ghborhood." Army physicians therefore recommend having a 

 wood if possible, between a marsh and an encampment. Beirut, formerly very un- 

 healthy, has ceased to be so since the planting of a wood of fir trees below the town. 

 At Paramaribo, the trade wind that regularly ventilates the town and renders it habit- 

 able, blows over a swamp within a mile of the town, but the malaria is arrested by an 

 intervening grove of trees. 



The effect upon the long unhealthy Maremme of Tuscany — by filling and draining 

 swamps and the planting of trees — may be also cited, whereby the health of the locality 

 has been essentially changed within the short space of one generation. 



Let us now see how these principles apply to the Prairie regions with which we have 

 so largely to deal. 



Whether with Prof. Lesquereux — (Geology of Ills., Vol. 1, Chapter VII.,) we hold 

 that the prairies have been formed by the gradual filling up, and consequent retro- 

 gression of vast lakes, and that the soil formed in this manner, being unfit and unsuited 

 for the growth of trees, they consequently remained treeless, or, with some, that they 

 were cleared by a more civilized race than the Indians, which race once inhabited these 

 regions — clearing the oak openings of Ohio, leaving their traces in the mounds and 

 fortifications still to be seen throughout the West, especially in Ohio, and were then 

 kept cleared by the Indian- by their annual burnings — the facts are that the pioneer 

 settlers found this a comparatively treeless region, with a peculiar vegetation, the sur- 

 face very generally moist, unless in the heat of summer, and, as is asserted by that 

 6trange myth — the oldest inhabitant — with a somewhat more equable and less intense 

 climate than now. 



In the comparatively few years that have passed since its settlement, wc find trees 

 springing up in the prairies, and extending themselves where they are not planted by 

 man ; the prairie grasses, whicli by their thick roots and herbage protected the BOi] from 

 gulleying and washing, have disappeared whenever cultivation has come in; the land 

 has become drier, even where drainage is not resorted to ; the streams have In-come less 

 constant ; agues and miasmatic diseases are becoming rarer, &c. <tc. Near Quincy were 

 several streams used by the early settlers of the country, some 30 to 35 years ago for 

 milling purposes, and furnishing an ample supply of water. Of one of the largest of 

 these, still known by the name of Mill stream, or Mill brook, it is difficult to conceive, 

 from its present appearance, that it could have been employed, so short a time ago, for 

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