" By these experiments it appears how very difficult it is to avoid the introduction of error.

One of your correspondents I observe, is disposed to ridicule the utility of these in- vestigations ; but he must be quite ignorant of their value in a physiological point of view.

There is, perhaps, no question in botany, which, at this moment, it is more desirable to settle on the sure basis of experiment, than the law which limits the variation of species.

I trust, therefore, that some other of your correspondents will lend their assistance in patiently experimenting upon the specific identity of different plants, and record all their failures as well as their successes, in each case ; for it will be only after a multitude of such experiments shall have been carefully performed, that we can expect to arrive scientifically and legitimately at the truth.

Mountains seen through a Haze which Solar Rays can scarcely pierce.