166 Mississippi Valley Horticultural Society. 



ber, but they have a strong claim, also, on the score of their reiDUted hygienic 

 relations. 



Tiiey have b^en largely pi inted in tin swampy regions of Algeria, where 

 they are reported to have produced marked effects upon the health of the 

 country bordering upon the marshy districts. The question arises, however, 

 whether the happy effect be due to their pleasant balsamic exhalations, or 

 perhaps more probably to their power of absorbing and assimilating im- 

 mense quantities of water from the swamps that Avere formerly so very un- 

 wholesome there. 



Here we must forego the advantages of the evcnhjpti, hnth is not at all im- 

 probable that in the miasmatic regions of our temperate zone, where the ex- 

 tremes of cold will not permit the introduction of the eucalypti, we may find 

 a valuable substitute for them in the stronger growing species of poplars and 

 willows. The Populus monilifera and nngulata, and the SaH.z alha have great 

 powers of absorbing moisture, and may rival the Australian trees as swamp- 

 drainers. 



HEALTH RESORTS. 



Pine forests have been highlj' reconnnended as health resorts, and some 

 virtue has been claimed for their resinous exhalations. These may possibly 

 exert a favorable influence in certain classes of disease, but it should also be 

 remembered that the hygienic conditions of any country depend largely 

 ui)on the geological character of the soil and its elevation above the sea-level, 

 Avith the attendant purity of the atmosphere and its hygroscopic condition. 

 Thus we find the most famous health resorts are usually situated upon land 

 that is well drained by a porous subsoil of sands, gravels and sandstones, or 

 underlaid by metamorphic rocks ; or they are found in elevated and moun- 

 tainous regions that are proverbial for absence of malaria; or, again, they are 

 well exposed to the salt air of the ocean, and, at the same time, away from the 

 exhalations of swamps and marshes. 



At the close of a valuable paper by Dr. G. L. Andrew, of Laporte, Indiana, 

 read before the American Health Association, appears the following sum- 

 mary of his argument, which is gladly reproduced : 



1. Forests increase the amount of condensation over their own areas, but 

 by reason of the amount intercepted by their leaves and stems the annual 

 rain-fall at the earth's surface is not, j^erhaps, materially affected by their 

 presence or absence in regions well covered with other vegetation and thor- 

 oughly cultivated. 



2. By means of their interlaced roots, mosses, lichens and humus, they 

 check the efflux of superfluous rain-fall, thus regulating the water supply in 

 streams and springs, and decreasing the proportion of the annual precipita- 

 tion that^is borne to the sea by the natural drainage of the country. 



3. Forests diminish the evaporation from the earth's surface, but this hy- 

 grometric deficiency is much more than compensated by the increased evap- 

 oration from their leaves. Forests may thus become beneficial, or otherwise, 



