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Show EXPLANATIONS. that these views are presented in tny book as c. rrectly a1 it was possible for me to give them, who am nothing but a general student: in one instance I have employed the language of a popular treatise (Dr. Lord's)-ridiculed by our reviewer as a book of no authority-merely because the ideas were there presented in a peculiarly intelligible form. The general aim was, I can honestly declare, to Almighty deviser might establish,, the forms of plants ? that Ruch crystallizations grow by simple apposition of new matter, and not from germs, as actual vegetables do ; tho question at issue being merely, whether the electricity concerned in the crystallization might not have some similar effect in uetermining the forms of the vegetables. I may here remark that I am not alone in surmising sorne common root for these phenomena. In Leithead1s Elect1·icil; (1837) the follo~Ving passage occurs:--" The form of the rout1~ of free electricity is modified by the medium through which it pac;ses, and also by the elec.tric state of such medium, or of that of the relative electrical condition of two bodies between which it is transmitted. If the medium through which it passes possesses a very inferior conrlucting power, it is obvious that a certain momentum must be requisite to enable the fluid to force its passage to · n given distance, and there will be a point at which the momentum of the fluid and the resistance of the body will exactly counterbalance each other; but so soon as the electricity has again accumulated to a sufficient degree to overcome the resistance, it will again force its way in another direction, until it arriv&s at another point of equilibrium. In this way we may re~dily see the modus ope1·andi of the electric fluid in Imparting regular forms to hodies; and it is highly probable that its actiOn in this respect extends to the vegetable kingdom , and perhaps operates even on animals, from the time in which they exist in the embryo state. . . . Another fact in support of the opinion, that the distincti'Ve forms of bodies are produced by electrical action, is, that crystals, and the twigs and ~eaves of vegetables, all terminate in points or sharp edges. so that the electrical action can proceed no further in increasing thf'l growth, or, in other words. in propelling fresh portions of matter i'.>r the extension of the plant, o::- the crystal, beyond the pointed or edged termination." In a letter of Mr. Crosse to Mr. Leithead, it is statecl that, in one of his experiments, there grew in the inside of an electrified jar filled with hydro-sulphuret of potash a mineral fungus, three-fourths of an inch in length and one-fourth of an inch in diameter. "in the shape of a common lrtt,mpet·nwutitetJ fnngus, which is Jonnd on f1·ees" " In one experiment," says Mr W Pekes, in a recent letter to myself, "a singularly beautiful elec· tro-vegetation was prouuced, a fo,.~st in rniniallwe, which, by aid of a good lens. presented many extraordinary appearances, and co·ntinned to interest me during many months." It may suit the reviewer anu others to scoff at such "resemblances;" but scof· fing will not unnul, in my mincl, the apprehension that there is here some relation of a very high interesting kind, the investigation of which may yet give us a deeper insight than we now enjoy in the mysteries of organic being. EMBRYOTIC REPRESENTATION8. 25~ con\ .. cy the doctrine of the epigenesis of anitnals, as M. Serres calls it, as an illustration of my subject, considering myself entitled to do so by the position which it has attained in the world. It is, of course, unfortunate for this, as it is for many other doctrines, th~t it should have an opponent; but this circumstance is fortunately, on the other hand, no adequate ground of condemnation in the judgment of third parties. I leave, then, the general tenor of this portion of my reviewer's objections, with the remark that, for the one authority which he has called into court, it would be easy to summon many as good on the other side ; for instance, Harvey, Grew, Lister, and Meckel. Our critic's own favorite authority-Mr. Owen -would give good evidence; see his Letters on the Invertebrated Animals, where he says that man's embryotic metamorphosis would not be less striking than those of the butterfly, if subjected like them to observation-and then adds, that the human embryo is first vermiform, next stamped with the characters of the apodal fish, afterwards indicative of the enaliosaur, and so forth. There is another tnost respectable English physiologistDr. Roget-who, in his Bridgewater Treatise, explicitly says, " that the anin1als which occupy the highest stations in each series possess, at the con1mencement of their existence, forms exhibiting a rnarkcd resemblance to those presented in the permanent condition of the lowest animals of the same series ; and that during the progress of their development they assume in succession the characters of each tribe, corresponding to their con~; ecutive order in the ascending chain." It is to what bas been thus spoken of by such excellent men-what was, I believe, first hinted at by Harvey, and afterwards shadowed forth by John Hunter-that this writer appJies the appellation of "a monstrous scheme, from first to last nothing but a pile of wildly gratuitous hypotheses." This reviewer and others have been eager to point out that " no anatomist has observed the shadow of any change assimilating the nascent embryo to any of the rauiata, mollusca, or articulata. Thus .are three whole classes [divisions] of the animal kingdom passed over 'Nithout any correspondin~ frntal type, and in defiance of the law of development." The writer here states what is not true, if any faith is to be placed in one of the first •uthorities of the ag '~J and one upon which he himself / / |