40 



Public Parks. 



"Whole families," says Mr. Bartlett, "have resided near the 

 Pontine Marshes, and, by the intenvention of shrubs and trees, have 

 escaped for years the noxious effects of the mephitic vapors v^hich 

 these putrid waters engender."* Dr. Hosack states that a famil}^ 

 in New Jersey was attacked with fever in consequence of cutting 

 down a wood that separated them from a morass in the neighborhood. 

 Befoi'e the operation they had been healthy. f "Army physicians, 

 therefore, recommend," says Dr. Wilson Philip, "having a wood, if 

 possible, between marshy grounds and an encampment." % Rigault 

 de Lisle calls attention to the fact that, upon Mount Argental, above 

 the village of St. Stephano, there is a convent which has lost all the 

 reputation for salubrity which it once enjoyed, since the lofty trees, 

 by which it was surrounded, have been cut down. " I have been 

 informed," he adds, "by persons worthy of credit, that in conse- 

 quence of the felling of the wood before Asterna, near the Pontine 

 Marshes, Veletri was visited for three successive years by diseases 

 which made much greater havoc than usual throughout the whole 

 country, and peneti^ated to many places which they had not pre- 

 viously been accustomed to reach. Rigault de Lisle cites other 

 cases, and refers to Volney, who states that Beyroot, formerly very 

 unhealthy, has ceased to be so since the Emir Fakr-el-din planted a 

 wood of fir-trees, which still exist, a league below the town. 



By Pliny and others, among the Ancients, it was supposed that 

 trees absorb the exhalations extricated from insalubrious places, and 

 that the beneficial effects obtained from woods are to be accounted 

 for in this way much more than the obstacles they offer to the diffli- 

 sion of these exhalations. This opinion has, to a certain extent, 

 received the sanction of Thouvenelle, Copland, and other modern 

 writers ; and it is is undoubtedly correct, as the results of certain 

 experiments made long ago, and ixpeated more recently, prove. 

 Dr. Lewis, of Mobile, says, "It is the received opinion that living 

 vegetation protects the human system from the deleterious effects 

 of malaria ; and, reasoning by analogy, it would appear that experi- 

 inents made by scientific men have satisfactorily explained the mutual 

 dependence of the animal kingdoms on each other for support. It 

 has been ascertained that if air, rendered pernicious by respiration, 

 be confined in a bottle, into which some green plant has been intro- 



* Thompson's ^«7;a/j. 

 t Practice of Medicine. 

 X Treatise on Feb. Dis. 



