Public Parks. ' 43 



the forest. Rigaud de Lisle obsei-ved localities in Italy where the 

 interposition of a screen of trees preserved everything beyond it, 

 while the unprotected grounds were subject to fevers."* The 

 belief that rows of trees afford an important protection against 

 malarious influences is very general among Italians best qualified by 

 intelligence and professional experience, to judge upon the subject. 

 The commissioners appointed to report on the measures to be 

 adopted for the improvement of the Tuscan Maremme advised the 

 planting of three or four rows of poplars, in such directions as to 

 obstruct the currents of air from malarious localities, and thus intercept 

 a great proportion of the pernicious exhalations." | Lieutenant 

 Maury believed that a few rows of sun-flowers, planted between the 

 Washington Obsei"vatory and the marshy banks of the Potomac, had 

 saved the inmates of that establishment from the intermittent fever, 

 to which they had been formerly liable. These experiments have 

 been repeated in Italy. Large plantations of sun-flowers have been 

 made upon the alluvial deposits of the Oglio, above its entrance 

 into the lake of Iseo, near Pisogne, and it is said with beneficial 

 eflects. I 



"In Southern Burmah the inhabitants place their houses under 

 trees with the best effect, and it was a rule with the Romans to 

 encamp their men under trees in all hot countries." § 



Many more instances of a like character might be adduced that 

 have occurred in this country, particularly in the West. In the 

 settlement of all new countries much sickness follows, owing to the 

 destruction of the trees and the upturning of the vegetable mould 

 which has for ages been collecting and lying dormant, and thus 

 exposed by the influence of heat and light to decomposition. The 

 " balance of nature, " as Dumas significantly expresses it, " is 

 destroyed," and as a necessary consequence the harmony is disturbed, 

 and sickness and death are the result to the disturbers. All the 

 operations of nature tend to produce unity and harmony in their 

 results ; and whenever man interferes with that order, it is at the 

 expense of his health and well-being. 



While preparing an article on cholera, as it appeared at Burling- 

 ton, Iowa, in 1850, I was forcibly struck with what I could not but 

 regard as the preventive influence of trees. In the houses on the 



* Becqueral, Des Climats. 



t Salvagnoli, Rapporto sul Bonificamenio delle Marennne Toscane. 



X II Politecnico, Milano, 1863. 



§ Parkes' Practical Hygiene. 



