Page:Popular Science Monthly Volume 35.djvu/845

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dity is such that a celebrated botanist has said of it that "if a single plant were uninterrupted in its possible increase for twenty-years, within that time it would cover an extent equal to the entire surface of the globe."

Our botanizing excursion, so successful, so full of interest, and so much enjoyed, having concluded, we bade adieu to matchless Killarney, and will not soon have effaced from our memories "the home of the ferns."


By Herr S. EXNER.

WHILE we endeavor to distinguish between instinct and reason, we are accustomed to speak of such skill and conformity of actions to a given end as are exhibited by birds in building their nests, or by societies of insects, as more resembling what we call reason. We may mark the difference, however, by observing that instinct develops its qualities only within a limited sphere and in view of a limited end. Birds can weave filaments into nests, attach them to branches, and adapt the forms of their work to those of the tree and its limbs; but their talents in weaving are of no use in helping them release themselves when caught in a snare, and they will then struggle as wildly and vainly as an animal that never built a nest. A hen will lay an egg every day in the same place till the quota is completed, and will then sit upon them; but many hens will sit all the same, and for the full time, if the eggs are taken away as they are laid. These examples illustrate how instinctive processes are produced simply as determined combinations—or work only in view of a special end. The actions provoked by them will remain the same, even when they have become purposeless. On the other hand, the associations of the processes can not be broken, and the skill which the bird directs to building her nest is not capable of being employed for any other end.

The more developed the instinct, the more stable are the combinations of phenomena and nervous conditions under which it works; the weaker the combinations, the more nearly the animal's mode of action approaches what we call reason. We should judge of the intelligence of an animal, not by single acts surprising to human understanding, but according to the diversity of the situations in which that animal can use its faculties. The weakness of reason in the animal always has the same character, and lies in the impossibility or difficulty of breaking certain associations and the incapacity to produce out of two combinations, by transferring a

  1. From a communication to the Sixty-first Congress of German Naturalists and Physicians.