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set up by birth, the proportion of fatty matter to the dried tissue of the lungs is from ten, twelve, fifteen, or eighteen to one hundred. But as soon as the air has entered the lungs, this proportion decreases to six parts to the hundred.

In all the affections of the chest, the consequence of which is to arrest permanently or transiently the respiratory act, in a greater or less extent, according to the extent of the lesion, the proportion of fatty matter increases in those parts rendered impermeable to the air. Under such circumstances, the rise in the quantity of such matters may be from fifteen to twenty, or thirty or forty, or even fifty parts to one hundred; whereas, in healthy portions of the same lungs, the proportion very rarely exceeds that of ten parts to the hundred. This fact hold good from the period of birth until advanced old age, in all cases where the lungs are obstructed by disease, or labour under phthisis. These organs, therefore, appear to undergo a fatty degeneration, which seems to be in relation with the absence of the contact of the air with the diseased parts.

The examination of lungs which are yet penetrated by air, notwithstanding extensive lesions, further supports this notion; for in such particular circumstances, the quantity of fatty matters extracted by means of ether is never equal to that afforded by portions of lungs in which air has ceased to enter during life.

According to the tables which the author has furnished, the greatest increase in the proportion of fat in the lungs takes place in phthisis, in which he has collected forty and even fifty-two parts in one hundred of desiccated pulmonary tissue. Here we may consider the fat to be derived both from the destruction of function of the lung, and also from the tubercular matter itself, which has long been observed to be mingled with much fat, so that it even seems but as a modification of that general pathological condition known as fatty degeneration.

Comparing lungs affected with pneumonia ;-in those which are quite impermeable to air, the proportion of fat rises to fourteen, sixteen, and twenty-four parts in one hundred; whereas in those which are yet permeable, its proportion is as six to one hundred, in two out of three cases; in the third, as eleven to one hundred.

M. Guillot observes, these variations in the quantity of fat in the lungs, according as the process of respiration is free or interfered with,-rising in the latter case,-are interesting to physiologists, and seem to indicate that a part of the fatty matter entering the blood becomes consumed in its passage through the lungs by the act of respiration. In cases of pneumonia and phthisis, where the lungs become impermeable to air, this fat begins to accumulate until its quantity equals, and even surpasses, that observed in the liver, in which the quantity of fat is so appreciable and considerable.

From experiments I am now making, (says M. Guillot,) I am led to believe that the section of the pneumogastric nerves, and asphyxia, produce in animals phenomena analogous to those above pointed

out.

Before quitting this matter, we would call our reader's attention to one point in the preceding paper which seems to us to have an important bearing on a much disputed point of medical jurisprudenceviz., the distinction between respiration and inflation, or insufflation, in the lungs, in cases of suspected infanticide. To determine this distinction is a great desideratum. Now, supposing the analyses of M. Guillot to be correct, can we not make use of them for the abovementioned purpose? He tells us, that as soon as the child has breathed, the quantity of fat in 100 parts of desiccated lungs diminishes but one-half at least, supposing the child to have arrived at the eighth or the ninth month of intra-uterine life. Thus, instead of the proportion of fatty matter being twelve, fifteen, or eighteen parts in 100, it is, by respiration, reduced to six parts. Now the question is, whether inflation will bring about this decrease of fatty matter as well as respiration. We should, á priori, think not; for this reduction of quantity is dependent on a vital action, and on certain chemical changes taking place in the blood under the influence of life. We can conceive how the pulmonary capillaries of the air-cells may become filled with blood by insufflation in a dead child, so as to resemble air-cells duly developed by respiration, but cannot understand how such a chemico-physiological change, as is the alteration of the proportion of fat in the lungs, can take place in such a manner, and after the extinction of life.

Be this as it may, the researches of M. Guillot are highly valuable in other respects, and are deserving of consideration and of repetition in this country; and if any relation or utility is perceived in them to forensic medicine, we shall have the merit of having directed the attention of the profession to them, and there will no doubt soon be inquirers in the same field to test the above researches in all their points of application.-Ibid.

Operating for Cataract under the Influence of Mercury.-M. Tavignot addressed a note to the Academy, stating that he looked upon mercurial salivation as a means of preventing many of the evils of inflammation after the operation for cataract. He seems to have imbibed this notion from the general observation of the influence of mercury in acute inflammation of the iris and cornea, and from considering that such a condition of those parts of the eye is what is to be feared after operating. He has put this idea to the test, having operated on three patients, who were just beginning to be affected by mercury, and in whom, too, there were some complications. He effected a perfect cure in from three to five weeks, having had no ills resulting from inflammation. The mercury is continued two or three days after operating, combined with extract of opium, so that the salivation induced may be most severe, just at the time when the ordinary precursors of iritis, or of corneitis, make their appearance-that s, about the third or sixth day after the operation.-Ibid.

THE

MEDICAL EXAMINER.

AND

RECORD OF MEDICAL SCIENCE

NEW SERIES.-No. XXXVI.-DECEMBER, 1847.

ORIGINAL COMMUNICATIONS.

Objections to the Theories of Franklin, Dufay, or Ampere, with an effort to explain electrical phenomena by the statical or undulatory polarization of omnipresent, ethereal, or ethereo-ponderable matter.* By ROBERT HARE, M. D., Emeritus Professor of Chemistry in the University of Pennsylvania.

1. It appears, from the experiments of Wheatstone, that the discharge of a Leyden jar, by means of a copper wire, takes place within a time so small, that were the transfer of a fluid from the positive to the negative surface requisite for its accomplishment, a current having a velocity exceeding two hundred thousand miles in a second would be necessary.

2. The only causes for the velocity of an electric current, according to Franklin, are the repulsion between the particles of the electric fluid, of which it has been assumed to consist, and

* Read before the Academy of Natural Sciences, and although ordered to be published in the forthcoming volume, has been excluded by matter having priority of date. Hence, to avoid procrastination-with permission from the Academy-it has been communicated to the obliging Editor of this work.

This commnnication might have been offered to the Journal in which those affiliated with the University usually make their communications, were it not that my friend, the editor, to an inquiry replied, that "nothing which is not directly applied to medicine" would be published in that channel.

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the attraction between those particles and other matter. These forces are alleged to concur in distributing the supposed fluid throughout space; whether otherwise void, or partially pre-occupied by conducting solids or fluids. Hence, when between two or more spaces, surfaces, or conducting masses, there is an unequal distribution of the electric fluid, the equilibrium is restored whenever a communication is opened, by means of a sufficiently conducting medium. Agreeably to this view of the subject, there seems to be a resemblance between the supposed effort of the electrical fluid to attain a state of equable diffusion, and that which would exist in the case of a gas confined in adjoining receivers, so as to be more dense within one than within the other; for, however the subtility of the supposed electric fluid may exceed that of any gas, there seems to be an analogy as respects the processes of diffusion which must prevail. But on the escape of any elastic fluid from a cavity, within which it may be condensed, evidently there must be a diminution of density, and of the consequent velocity of efflux, proportionally as the quantity left in the cavity diminishes, so that the latter portions would move with extreme slowness. Far from taking place in an analogous manner, electrical discharges are effected with an extreme suddenness, the whole of the redundancy being discharged at once in a mode more like the flight of a bullet, projected with infinite velocity, than that of a jet varying in celerity from a maximum to a minimum.

3. So far, in fact, is an electrical discharge from displaying the features which belong to the reaction of a condensed elastic fluid, that agreeably to the observations of Henry, the result is more like the vibrations of a spring, which, in striving to regain its normal position, goes beyond it. The first discharge between the surfaces of a Leyden jar is not productive of a perfect equilibrium. The wave-like transfer of different polarities goes beyond the point of reciprocal neutralization, producing a state, to a small extent, the opposite of that at first existing; and hence a refluent discharge ensues, opposite in direction to the primary one. But even this does not produce an equilibrium, so that a third effort is made. These alternate discharges were detected by means of the magnetism imparted to needles exposed, in helices, to the consequent current, more properly called polarizing undulations or waves.

4. Supposing one or more rows of electrical particles, forming such a filament of electricity as must occupy the space within a wire of great length, to be made the medium of discharge to a Leyden jar; agreeably to the hypothesis of one fluid, the electrical filament must be attracted at one end of the wire, and propelled at the other, as soon as its terminations are brought into

due communication with the coatings of the jar. Yet the influence of the oppositely charged surfaces of the jar cannot be conceived to extend to those portions of the electricity which are remote from the points of contact, until they be reached by a succession of vibrations. Hence it is inconceivable that every particle in the filament of electric matter can be made at the same time to move, so as to constitute a current having the necessary velocity and volume to transfer, instantaneously, the electricity requisite to constitute a charge. Even the transmission of the impulses, in such an infinitesimal of time, seems to be inconceivable.

5. In reply to these objections, it has been urged by the Franklinians, that a conductor being replete with electricity, as soon as this fluid should be moved at one end, it ought to move at the other. This might be true of an incompressible fluid, but could not hold good were it elastic. A bell wire moves at both ends when pulled only at one; but this would not ensue were a cord of gum elastic substituted for the wire.

6. But if the flow of one fluid, with the enormous velocity inferred, be difficult to conceive, still more must it be incomprehensible that two fluids can rush with similar celerity, from each surface of the jar, in opposite directions, through the narrow channel afforded by a wire; especially as they are alleged to exercise an intense affinity; so that it is only by a series of decompositions and recompositions that they can pass each other. That agreeably to the theory of Dufay, equivalent portions of the resinous and vitreous fluids must exchange places during an electrical discharge, will appear evident from the following considerations:

7. One surface being redundant with vitreous and deficient commensurately of resinous electricity, and the other redundant with the resinous and deficient of the vitreous fluid, it is inevitable that to restore the equilibrium, there must be a simultaneous transfer of each redundancy to the surface wherein there is a deficiency of it to be supplied. If after decomposing a large portion of the neutral compound, previously existing on the surfaces of the jar, and transferring the ingredients severally in opposite directions, so as to cause each to exist in excess upon the surface assigned to it, were the redundancies, thus originated, to be neutralized by meeting in the discharging rod, neither surface could recover its quota of the electrical ingredient of which it must have been deprived agreeably to the premises.

8. This calls to mind the fact, that no evidence has been adduced of the existence of any tertium quid, arising from the union of the supposed electricities founded on any property displayed by their resulting combination in the neutral state. It must, if it exists, constitute an anomalous matter, destitute of all properties, and of the

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