You tell your readers in your January number, what I suspect most of them were previously unaware of, that the action of the Eucalyptus is-not curative but preventative; that is to say, the plant rapidly acts through its roots instead of its leaves, taking up with the former the moisture which, if left to be acted upon by the sun's heat, would produce unwholesome vapors. These ever-thirsty roots create innumerable streams in the soil, and so prevent stagnation and its unpleasant results.

Can you tell me whether the sun-flower - the large-flowered one grown in gardens - acts in a similar manner; as it also comes strongly recommended as a "destroyer of fever in the air".

We are told that it was some years since grown around the grounds of a certain hospital at or near Washington, where ague had previously been very prevalent. The result, we are further assured, was the complete elimination of ague from within the area named, a result which it is difficult to understand as being produced either by the absorption of the poison through the leaves or the extreme moisture by the plant's roots.

The sun-flower, though a rank grower, is a puny affair as compared with the Eucalyptus, which must spread out its roots either horizontally or vertically to a great distance. If the sunflower's action coincides with that of the Australian plant, then one would suppose that it should be grown thickly like a grain crop, covering the entire ground. As the broken stalks of the sunflower are an excellent substitute for the corncob as kindling, and as the seeds are greatly relished by poultry, it would not be an altogether unprofitable work for those living in localities afficted with the ague, to give the plant a thorough test as regards its sanitary value.

Have any other plants been successfully tried for a like purpose in another climate, or could you name any which it would be worth while to try experiments with?

[There are few trees better adapted to dry up marshy land than Willows and Poplars. The roots drink up enormously. It is the cheapest kind of underdraining.

We have no doubt that any plant that will aid in ridding the soil of superabundant moisture, is so far a benefit to public health. - Ed.G.M].