Moreover, a second Monk, the Clover Bombyx, nearly akin to the first and, like him, superbly plumed, sets us an exceedingly perplexing problem. He is fairly plentiful around my place; even in the enclosure I find his cocoon, which might easily be confused with that of the Oak Bombyx. I am deceived at first by the resemblance. Out of six cocoons, from which I expected to obtain Banded Monks, six females of the other species hatch at the end of August. Well, around those six females, born in my house, never a male appears, though there is no doubt that the tufted ones are present in the neighbourhood. If spreading feathered antennæ are really organs for receiving information at a distance, why are not my richly-horned neighbours informed of what is happening in my study? Why do their fine plumes leave them indifferent to events that would bring the Banded Monk hastening up in crowds? Once more, the organ does not determine the aptitude. This one is gifted and that one is not, despite organic similarity. CHAPTER XIII THE SENSE OF SMELL In physics we hear of nothing nowadays but the Röntgen rays, which penetrate dense bodies and photograph the invisible for us. A fine discovery, but how insignificant in face of the surprises which the future reserves for us when, better-informed of the why and wherefore of things, we supplement with art the feebleness of our senses and succeed in rivalling, be it ever so little, the keenness of perception revealed by the brute creation. How enviable, in many cases, is this animal superiority! It teaches us the poverty of our attainments; it declares the mediocrity of our sensory apparatus; it gives us evidence of impressions foreign to our nature; it proclaims realities so far in excess of our attributes that they astound us. A wretched caterpillar, the Pine Processionary, splits his back into meteorological air-holes which snuff the coming weather and foretell the squall; the bird of prey, with its incomparably long sight, sees from high in the clouds the Field-mouse squatting on the ground; the blinded Bats guide their flight without injury to themselves amid Spallanzani’s [32] inextricable maze of threads; the Carrier-pigeon, though moved a hundred leagues from home, infallibly regains his cote across immensities which he has never traversed unaided; within the limits of her humbler flight, a Bee, the Chalicodoma, [33] also spans the unknown, accomplishes a long journey and returns to her mass of cells. The man who has never seen a Dog hunting for truffles does not know one of the finest achievements of the sense of smell. Absorbed in its functions, the animal trots along, with its nose to the wind, at a moderate pace. It stops, questions the ground with its nostrils, scratches for a few seconds, without undue excitement, and looks up at its master: “Here we are,” it seems to say, “here we are! On my word of honour as a Dog, there’s a truffle here.”