Page:Science vol. 5.djvu/79

 LETTERS TO THE EDITOR. Tbe mtukrxt camJToroua.

I aAVK seldom been more surprised tban at the staW- ment that the carnivi.rtma habits of the muskrat have but just been discoTered by scientific men. They ■re »o (iflen menlioned in treatises on Araericau con- chology, that a little reading would have prevented the error. Thus Dr. Jamps Lewis aays of the Unl- onldae.  They aJford abundant fuod fur the muskrat and mink; and like iiuolations might be given. But the fact is not left out of sight in treatises on the Rodentln. In the ' Mammalia of New York,' published by the st«t«, De Eay aaya of the muskrot, " It Is also extremely fond of the fresh-water mussel lUnio), heaps of which, in a gnawed or eomminuted state, may be found near their retreats.'' Tonney's 'Zoiilogy,' a mere schoolbook, says, "Uuskrats feed upon mussels, and roots of grasses, and aquatle pUnla." To my knowledge, they feed on Unios Ihroiichout the year, but mostly In winter and spring. The floor of my boat-house is covered with shells, left by muakrats, ererj spring; and I have often stopped at the heaps of shells by their boles to see what ■pe(leB occurred near. The fact that they eat fish has cerlaial; been less known.

There seem to be four principal ways In which luntkrals get at the auimal in the mussel-shell. In a small lake near me there are very fine specimens of Anodonla fragitis, but In such situations that it is Almost Impossible to get the finest ones alive. The •hells are large, but almost like paper; and the musk- rat invariably tears off one valve. In the thicker shells of Seneca River, not far off, its common way is to break the thinner end of the shell. In the mach heavier shells of the west and south, I have beard that Ihey either gnaw the hinge-ligament, or allow the animal to freeze and open,

While speaking of the Unloiiiilac, I may mention a corious circumstance. Very few of their shells are to be found on one shore of Onondaga Lake, which is flat and marly; and this is parti; so because the animal burrows deeply In the tenacious mud, and is not easily dislodged. But 1 passed that shore one day when a number of Atiodonta Benedictii were wubed in. They were helpless in the waves; but, when Ihey had rested a while on the beach, they got """ "i> edge, protruded the muscular foot, got a finn on the marl, and worked their way buck to the !r with apparent ease. W. M. Beauchamp.

enaiu of halluciuatioaB. In a letter which you published on Dec. 5, I men- tioned a sort of census whereby we are inquiring what proportion of the population has experienced waking visions of absent friends; the abject being to discover how far cAance may account (or the numer- ous cases where such hallucinations have coincided with the death lor some serious crisis in the life) of the person vrhose presence was suggested, or how far, on the other hand, these cases drive us to some such hypothesis as ' telepathy.' In a letter published bjr you oti ihi- same day. Professor Newconib has objected that untrue answers may be given by per- sons willing to amuse themselves at our expense. I am Car from denying that persons may exist who wmild be glad to thwart us, and amuse themselves. even at the cost of untruth. But when the gueslion Is put. "Do you remember having ever distinctly seen the face or form of a person known to you, when tliat persuu was not really there ? " It Is not at once ""-■ - whether the amiwinj/ untruth would be ' yes '

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��or ' no.' In neither ctse would the joke seem to b« of a very exhilarating quality: but, on the whole, I should say that 'yes' would be the favorite, as at any rate representing the rarer and less commonplace experience. ' Yes ' is, moreover, the answer, which. as a mutter of fact. It has been very generally thought we ourselves preferred ; so that to give it might pro- duce a piquant sense of fooling us to the top of our bent. But a moincnfn reflection will show, that, su far as the census might be thus affected, it would be affected In a direction adeerDe to the telepathic argument; for the commoner 111 c purely casual hal- lucinations are reckoned to be. the stronger is the argument that the visions which correspond with real events do so ftj/ chance. And it the numlwr of these coincident visions makes the chance-argument untenable, even when the basis of estimation Is af- fected in the way supposed, a fortiori would this be the case it the j/es™ were reduced to their true number.

While on this point, I may add that in such a cen- sus as ours there are reasons why, quite apart from untruth, an imfalr number of yentM are sure to be obtained. One chief reason is, that, when forms to be filled np are distributed on a la^ scale, it is impossible to bring it home to the minds of many of the persons whose answer would t>e ' no,' that there is any use in recording that answer. Their In- stinct is, that results, to bo of scientific value, must be positive, like natural-hisMry specimens. Thia difficulty has been encountered again and again; and I feel little doubt that the proportion of yeses to noes will in the end be quite double what it ought to be: la other words, the telepathic argument, if it pre- vails, will prevail, though based on data distinctly unfavorable to It.

As Professor Newcomb seemed to eonSne his objec- tion to the results of the census, I need not occupy your space with a description of the various precau- tious bif which we ascertain that our cases of coin- cident visions— of reridlcaf hallucinations — are bona j!!Je records. Suffice it to say, that, whatever the pos- sible sources of error in our evidence maybe, — and there are some which demand unceasing care and watchfulness, ~ deliberate hoaxing is a danger which we believe we can reduce to an amount that will not affect the validity of our general conclusions. EuMDND Gurnet, Hon. sec. of Soc for foyeli. research.

��Prof. A. R. Crandall, of the Kentucky geological survey, has recently discovered in Elliot county, of that state, several dikes of very interesting peridotite, which intersect the carboniferous formation. It very rarely happens that such youthful felspar-tree, ma»- slve rocks occur in r^ons of so little disturbance as eastern Kentucky, and under such cireumstances that their eruptive character can be established beyond question. Professor Crandall and myself, with the approval of the U. S. geological survey, hope to be able to give these rocks the careful study they ought to receive. .1. S. Dillxr.

��Iiake nUstasainl.

Tour contributor, Prof, J. D. Whitney {Science,

No. 100), is quite mistaken in ascribing the receut

newspaper paragraphs referring to Lake Mista.i^'lni

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