382 BOTANICAL GAZETTE [OCTOBER 
xylol under the tap before pouring in the paraffin. The latter step 
requires only slight practice to be successful, and indeed the only effect 
of a too rapid pouring in of the melted paraffin seems to be the formation 
of strings of paraffin reaching down into the xylol. If the paraffin plug 
needs to be removed at any time, this can be accomplished readily by 
forcing through it a hot needle, the tip of which has been bent at right 
angles. The needle after cooling for an instant may be turned slightly 
and the plug pulled from the vial—T. H. Goopsprep, University of 
California. 
ADAPTATION AND NATURAL SELECTION 
I wish to correct a false impression which my paper on the agency 
of fire in the propagation of the longleaf pines (Bor. Gaz. 64:497-508. 
1917) has left in the minds of some of my correspondents, to whom 
it seems that the conclusions there reached might lead to the absurd 
economic paradox that forest fires should be encouraged for the con- 
servation of our pine lumber supply. As a matter of fact, all the evi- 
dence produced in that paper was intended to show that it is their 
adaptation for resistance to fire which insures the survival of this species. 
The action of natural selection in this case, as in practically all others 
that have come under my observation, is negative and indirect. It 
preserves not by selection of the fit, but by elimination of the unfit, thus 
giving the best adapted a free hand in the struggle for existence. 
In calling attention, therefore, to the peculiar relation between the 
longleaf pine and fire, there was no thought of suggesting that we should 
imitate the method of nature; but having learned that a clean forest floor 
and plenty of sunshine are essential conditions for the propagation of the 
longleaf pine, these conditions may be secured by other means than fire, 
such as judicious cutting and thinning, and a periodic cleaning up of the 
forest floor. Whether a well guarded ground fire at the proper season 
might not be a useful aid in accomplishing this last purpose is a ques- 
tion which must be left for the practical forester to decide—E. F. 
ANDREWS, Rome, Ga. 
