that these gentlemen were deceived when they believed the motions to be produced by a fingle metal. He himself thought that he had produced them fo, but, on paying more attention, he difcovered that two metals, of which one touched the animal, were really in contact. Having fhewn in what refpects this new influence is not analogous to electricity, accumulated by the animal powers, he adds that it is not, in his opinion, derived from the metals alone, but that animals contribute to its production. We fhall leave the curious reader to compare the author's reafons on this head with thofe adduced by M. Volta on the oppofite fide of the queftion; confeffing that, in the prefent ftate of the inquiry, we incline to think with the Jatter; though fome fmall difficulties may remain to be cleared up. In the larger and more interefting part of his book, Mr. F. relates experiments, in which he uses the power of the metals to produce mufcular action, as a teft in fome important phyfiological inquiries. Many of the facts which he defcribes are curious, and feveral, we think, important. Among the former, we rank the following: • I had laid a leech upon a crown piece of filver, placed in the middle of a large plate of zinc. The animal moved its mouth over the furface of the filver, without expreffing the leaft uneafinefs; but having ftretched beyond it, and touched the zinc plate with its mouth, it inftantly recoiled, as if in the mott acute pain, and continued thus alternately touching and recoiling from the zinc, till it had the appearance of being quite fatigued. When placed wholly upon the zinc, it feemed perfectly at its eafe; but, when at any time its mouth came in contact with the filver lying upon the zinc, the fame expreflion of pain was exhibited as before. With the earth worn, this experiment fucceeded ill more decifively. The animal prang from the zine in writhing convulfions; if, when the worm firetched itself forwards, one of its folds lit upon the zinc, it expreffed little uncatinefs in compariton of what it flowed when the point of its head touched the zinc.' Mr. F., in a great variety of inftances, found the heart affecled by placing one end of a rod of pure filver in contact with one fide of its nerves and blood-velicis, and one end of a rod of zinc on the other, both at one-third of an inch diftance from the auricles; and afterwards bringing the opposite ends into contact.' In the ufual way of making the experiment, no contraction of the heart is produced. On introducing a filver probe into one ear, and a roll of tin foil into the other, Mr. Fowler felt a difagreeable jirk in his head; in the night following, an hæmorrhage from one ear occurred. On placing tin-foil on his tongue, and making a filver pencil-cafe touch the eye-ball, he faw a flash of light. لا light. Thrufting a filver rod as highly as poffible up his noftril, and bringing it into contact with zinc on the tongue, he saw a ftronger flash; and his friends obferved a distinct contraction of the pupil, whenever the metals were made to touch. In thefe experiments, Mr. F. thinks that the effect of the metallic application to the nafal branch of the firft divifion of the fifth. pair of nerves is propagated through the ciliary ganglion, along the ciliary nerves, and to the choroid coat, whofe veffels it excites into inftantaneous action; and that their action again, by ftimulating the retina, occafions the fenfe of light.We do not, however, fee the cogency of the almoft pofitive proof' which he afterward quotes, that vifion depends on the ftimulus given to the retina by the activity of blood veffels in fome part of the eye.' The cafe in queftion feems only to fhew that inflammation had rendered the eye exceedingly fenfible to a very faint light. We fhould rather deduce from it the probability that all bodies are folar phofphori. The bloodveffels of the web of a frog's foot feemed to Mr. F. to be stimulated by the influence of the metals: his friends could not perceive the fame effect. This was, of neceffity, a microfcopic experiment. The following fact is remarkable: If, after having divided at the pelvis a frog recently killed, the fciatic nerves be freed from cellular membrane up to their origin from the fpine, and all the parts below this, except themfelves, be cut away, the mufcles on each fide of the fpine, for fome little way up, may be brought into contraction by touching the nerves alone with the two metals in contact. This experiment has not always fucceeded with me, and never unless the frog had been recently killed. So long as the hind legs remain undivided from the nerves, it never fucceeded; the only contractions produced being in the legs.' The inquiry, how far nerves and mufcles derive their power from the brain on the one hand, and from the fanguiferous fyftem on the other, is equally interefting and well conducted. In the experiments, the communication of certain parts with the brain and the fanguiferous fyftem was interrupted; thofe parts were fimilar in different animals, and fometimes in the fame animal. After the interruption had continued for fome time, the metals were used as the test of its effect. On the whole, it appeared that the fanguiferous fyftem contributes more immediately than the brain to the fupport of that condition of mufcles and nerves, on which contraction depends; fince that condition was found to be much more injured by intercepting the influence of the former than of the latter.-Some experiments follow, which fhew, contrary to M. Fontana's opinion, that opium and poifons do not act on the blood. Mr. Mr. Fowler attefts that the mufcles of the pofterior extremities remain contractile long after the heart. He obferves that, on applying the metals to a nerve, every muscle, to which that nerve is diftributed, contracts :-but no mufcles, he fays, are made to contract by applying them to the brain or fpinal marrow, except fuch as derive their nerves from the part immediately in contact with the metals *. Profeffor Robinfon has fupplied Mr. Fowler with a few remarkable facts, from which we fhall felect the following: Put a plate of zinc into one cheek, and a plate of filver, (a crown piece) into the other, at a little diftance from each. Apply the cheeks to them as extenfively as poffible. Thruft in a rod of zinc between the zinc and the cheek, and a rod of filver between the filver and the other cheek. Bring their outer ends flowly into contact, and a smart convulfive twitch will be felt in the parts of the gums fituated between them, accompanied by bright flashes in the eyes. And thefe will be diftinctly perceived before contact, and a fecond time on feparating the ends of the rods, or when they have again attained what may be called the ftriking distance. If the rods be alternated, no effect whatever is produced." After what we have faid, it is hardly neceffary for us to fubjoin a recommendation of this treatife. The reader of it will find many curious minutiæ, which we have been obliged to pass over, and many important things detailed at length on which we could only touch. It feems to us that Mr. F. in attempting to discover electricity by irritating frogs in connection with M. Volta's condenfer, applied them wrong, and therefore could not fucceed. We fhould fuppofe the nerve to be irritated by electricity paffing from the filver, which is Having laid bare the brain of a living frog, and put a stop to its fpontaneous motions, by gently preffing upon the brain, I introduced a long flip of tin-foil doubled underneath a part of the skull, which had not been removed, and placed a filver probe upon its tongue. The only mufcles which contracted, when the tin-foil was bent over the nofe of the frog, fo as to come in contact with the probe, were thofe which move the eyes, and the transparent membrane which defends them, thofe of the tongue and of the throat. When the tin-foil was twitted into a thin roll, and paffed a little way down the fpine, the mufcles of the upper extremities and of the thorax contracted; when a little further, thofe of the back and of the abdomen contracted; and when introduced ftill further, to where the fciatic nerves leave the fpine, the pofterior extremities were, for the first time, ftrongly convulfed. I have repeated this experiment very frequently; and have always found, that, as foon as the fpontaneous motions of frogs had ceafed, the contractions, excited by the metals, were uniformly progreffive from the head downwards, correfponding exactly to the progrefs of the metals down the spine.' naturally naturally pofitive, to the zinc, which is negative; how, therefore, while they are applied to the fame fide of the inftrument, can they change its electricity? By applying filver and zinc alternately to the oppofite plates of Mr. Bennet's doubler, its electricity may be changed at pleafure, whence there can be no doubt of the real electrical influence of the metals :-but this part of the fubject will perhaps foon be illuftrated by a more expert electrician than even Mr. F. feems to be. Bea...s. ART. X. Letters from Dr. Withering of Birmingham, Dr. Ewart of The letter from Dr. Withering confifts of various practical remarks relative to different topics mentioned in Dr. B.'s observations on confumption. The fact, which is moft to the purpofe of Dr. B.'s theory, is that the only claffes of men, which Dr. W. has obferved to be totally exempt from confumptions, are butchers, and the makers of catgut. We cannot fay that our experience, as to the former of these claffes, is perfectly conformable to this remark. The letter from Dr. Ewart relates two pulmonic cafes, in which mephitic air was tried. The firft is that of the late Hon. Col. Cathcart, and it amounts to no more than fome imaginary relief produced in a mortal difeafe. The fecond is that of a young lady, who, after a violent pleuritic feizure in Ruffia, ending in fuppuration, fell into a tabid state, and came to England with fymptoms which feemed to indicate a confirmed phthifis. After a liberal inhalation of the air rifing from vitriolic acid poured on marble, the loft her hectic fever, and gained flesh and ftrength. This progrefs of amendment was interrupted by fresh inflammation, which being fubdued. by bleeding and other remedies, the mephitic air was again. applied with advantage. A fecond relapfe was fucceeded by fimilar events. At length the returned by fea to Ruffia, and has fince been in a state of progreffive recovery. Dr. Thornton, by his communications, feems to be a thorough friend to the new fyftem, and anxious to catch every circum, stance in its favour from even the most common occurrences in practice. We, who are paft the age of "believing all things and hoping all things," cannot travel quite fo faft in our progrefs to conviction. We wish that the letter from Dr. Biggs, defcribing his own cafe, had been fomewhat more particular. It appears that a kind of afthmatic paroxyfm, returning every night, which had refifted various remedies and change of air, was radically removed after having infpired, for eight days, a mixture of one part of oxygene with three of atmospherical air, thrice a day, from five to twenty minutes at a time. The account was written, however, only three weeks after leaving off the remedy. A curious cafe of epileptic affection follows, related, as appears, by Dr. Beddoes himfelf; in which, oxygene air occafioned a kind of intoxication, like the effects of opium. This did not totally difappear till 52 hours after the laft infpiration of the air. The epileptic fits had been fufpended for three days before this happened, and the patient feemed better than ufual. An abstract of M. Vauguelin's experiments on the liver of the Skate is next given. It is adduced to fhew a connection between a deficiency of oxygene and the formation of fat. The paper on the ufe of yeaft in putrid fevers, by the Rev. [and benevolent] Edmund Cartwright, exhibits one of the most aftonishing examples of fuccefsful practice that medical history affords. In three or four detailed cafes, a few fpoons-full of yeaft feem almost inftantly to have recovered the patients from a dying ftate to perfect fafety; and Mr. C. afferts that, in nearly fifty cafes of fevers of the low and putrid kind among the poor, in which he employed yeaft (together, indeed, with other appropriate remedies,) he did not lofe one patient. We know that thefe relations deferve every degree of credit, and it will be inexcufable in the facul y not to repeat the experiment. A cafe, communicated by Dr. Parry of Bath, of various fymptoms of defective refpiration, ending in death, in which the right lobe of the lungs was found to be little more than a plexus |