to the impossible.  He says this, always:—­Here we have certain interesting phenomena; their causes are involved in mystery impenetrable; their esoteric nature is beyond the reach of any microscope;—­what then?  My Heaven! let us do what we can with them.  Let us seek out their relations; let us investigate the laws regulating their interdependence,—­if there be such laws; and apres, let us inquire if there be any practical results obtainable from such relations and laws.

“You follow me, Monsieur? Eh, bien! This was the system, and Cesar Prevost came speedily to one law,—­a law so important, that, like Aaron’s serpent, it put all the rest out of sight forever, engrossing thereafter his whole attention.  This law, which pervades the entire animal economy, and is of course important in proportion to its universality, is as follows:—­The sympathetic harmony between animals, other things being equal, is IN INVERSE PROPORTION to their rank in that scale of comparison in which man is taken as the maximum of perfection. Consequently, man is most deficient in this instinctive something, which, for lack of a better term, I have ventured to style ‘sympathetic harmony,’ while the simplest organization has it most developed.  This last, you perceive, Monsieur, is only inductively true;—­when we get below a certain stage in the scale, we find the difficulties of observation increase in a larger ratio than the augmented sympathy, and so we are not compensated; ’t is, for instance, like the telescope, where, after you have reached a certain power, the deficiency of light overbalances the degree of multiplication.  Knowing this, my first aim was to find out what animal would suit best,—­what one that could be easily observed was most susceptible, most sympathetic.  ’T was a long labor, Monsieur; I shall not tire you with the details.  Enough that I found in the snail the instrument I needed,—­and in the snail of the Rocky Mountains the most perfect of his kind.  You smile, Monsieur. Eh, bien! ’t is not philosophic to laugh at the means by which one achieves something.  Smile how you will, ’t is a fact that in the snail which is so common and grows to such an enormous size in the valleys and on the slopes of your great Cordilleras I found an animal combining a maximum of sympathetic harmony with the greatest facility of being observed, the best health and habits, and the utmost simplicity of prononcee manifestation.  But, you ask, what seek I, then?  My Heaven, Monsieur! there was the grand Idea,—­the Idea upon which I build my pride,—­the Idea that is mine! When it came to me, Monsieur, this Idea, a great calm filled all my soul, and I felt then the spirit of Kepler, when he said he could wait during centuries to be recognized, since the laws he had demonstrated were eternal and immutable as the Great God Himself!  Yes, Monsieur!  For in that crude, undeveloped Idea were already germinating the wonders of an achievement grander than any of Schwartz, or Guttenberg, or Galileo.  Oh, this beautiful, grand simplicity of Science, which was able, from the snail itself, the very type and symbol and byword of torpidity and inaction, to evolve what was to conquer time and space,—­to outrun the wildest imaginings of Puck himself!”