SECRETARY'S PORTFOLIO. 303 



facts to support it, in whicli lie wtis certaitily very industrious; but it would 

 have been better and more in accordance with the deductions of true science, 

 to have framed his theories after he had obtained and arra!iged his facts. 



John J. Thomas. 



TREES AND MIASMA, 



So much iias been said within the last few years of the value of the 

 eucalyptus, or Australian gum-tree, in destroying or neutralizing the miasma 

 of malarial districts, that it would be well that experiments be made with 

 various plants for this purpose, especially those having large, and particularly 

 those having downy leaves, as well. The common sunflower is well known for 

 its so-called value in preventing the bad effects of miasma. There are 

 undoubtedly many others as good, and that may as easily be grown. jMarshy 

 lands are harmless if the vegetation in decaying does not give o2 putrescent 

 gases, for mere moisture is not unhealthy. Hence marshes become pestiferous 

 if accumulations of vegetable matter exist, which, under the effects of sufficient 

 heat and moisture, give off putrefying matter. In the North marshes are not 

 deadly for the reason that the summer heat is not sufficient, as a rule, to 

 produce putrid fermentation to a degree sufficient to produce any but the 

 lighter forms of malarial diseases. 



The business of plants is to pump up and utilize those noxious matters, and 

 utilize them in their structure, while at the same time they give off oxygen by 

 their leaves. Hence marshes which abound in a variety of plants are not 

 usually deadly. The most noxious are those which dry up in the summer and 

 leave the mud exposed to the action of the sun. Hence the most potent 

 means of obviating its effects is to plant the margins with some broad-leafed 

 trees, and preferably those that are pubescent or downy, as the basswood. "We 

 have before this advised the planting of sunflowers in miasmatic neighborhoods, 

 and hope to see it acted on the coming season. We also hope that those who 

 do so will make the results public. — Prairie Farmer. 



DISPERSAL OF SEEDS. 



The thistle, the dandelion, and the cotton bush provide their seeds with long 

 tufts of light hair, thin and airy as gossamer, by which they are carried on 

 the wind to bare spaces, away from the shadow of their mother plant, where 

 they may root themselves successfully in the vacant soil. The maple, the ash 

 and the pine, supply their embr3^os with flattened wings, which serve them in 

 like manner not less effectually. Both these we may classify as wind-dispersed 

 seeds. A second set of plants have seed-vessels which burst open explosively 

 when ripe, and scatter their contents to a considerable distance. The balsam 

 forms the commonest example in our European gardens ; but a well known 

 tropical tree, the sand-box, displays the same peculiarity in a form which is 

 almost alarming, as its hard, dry capsules fly apart with the report of a pistol, 

 and drive out the disk-sliaped nuts within, so forcibly as to make a blow on 

 the cheek decidedly unpleasant. These we may designate as self-dispersed, 

 seeds. Yet a third class may be convenientlv described as animal-dispersed, 



