ADAPTATION AND SELECTION IN >fATDRE. Ill 



biologists would glailly apply, if they could, to tho living, 

 growing, developing organic life around us. But the facts of 

 biology do not lend themselves to such simple handling, and 

 by no less an authority than Weismann we are warned that, 

 in binlogv we come upon the unknown sooner than in any 

 other branch of science, so that here, more tluin elsewhere^ 

 is a hasty making of ambitious " laws " to be especially 

 guarded against. 



But much more significant forms of adaptation meet us 

 as soon as we turn from the inorganic to the orgauic, and the 

 great range cf the latter, and the immense diversity of their 

 environments, are illustrated by a bacterium at one end, and 

 man at the other, of the great chain of life. The former iu 

 its fluid medium can move, can absorb nutriment, and in, 

 response to certain simple stimuli can manifest what the- 

 extreme mechanically-minded biologist will call free-will and 

 choice. The bacterium is adapted to its simple home, and 

 the latter is adapted to tlie life of bacteria, among other 

 properties it possesses. There are thus two of our meanings 

 of adaptation fuliilled, and the third, viz., that of the purpose 

 for which it is adapted, may be beautifully illustrated in the 

 case of those simplest bacteria of putrefaction which from 

 the beginning of life on the globe have exercised their 

 beneficent function as scavengers of a decaying and 

 developing world. It is needless to point out that if 

 organisms require oxygen to respire, and nutriment to 

 absorb, they require only in a little less important degree, 

 when they die, to be disintegrated, for the benefit of tha 

 succeeding population of the globe, by means of these 

 humble bacteria of putrefaction so recently discovered 

 through the genius of Pasteur. 



Between this lowly instance of adaptation, in which 

 profoundly important issues lie enwrapped, and man himself, 

 there lie open to our scrutiny and admiration a world of 

 adaptations, extrinsic and intrinsic, incalculable in number 

 and beneficent in purpose. 



Another side of the question of adaptation is opened up 

 when, in addition to the means to ends which every organism, 

 vegetable and animal, presents for its own benefit, we look at 

 the great question of the environments provided for these 

 various organisms. The means are wonderful, the ends are 

 beneficent, but they require a Jield in which to Avork. The 

 key of a Chubb's lock is an instrument interesting enough 

 to a mechanician, wlio may admire the finish and complexity- 



