or addicted to exceffes in the article of women, as was Francis his father, and as his brother Leopold is well known to be at this time. ......Affiduous, rather than tender, moderate in all his defires, and content with the fociety of his miftrefs, he is a companion, not a lover. His amours, when he has had any, have always been of fhort duration, managed with privacy, and unaccompanied either with fcandal or expence,' Vol. ii. P. 432,

We have before had occafion to commend Mr. Wraxall as a pleafing writer; and the prefent volumes do not induce us to relinquifh our former opinion of him. The work affords. much amusement and information; the characters are well drawn; and, though a careleffnefs of flyle is occafionally obfervable, the diction is fometimes not inelegant.

Annals of Medicine, for the Year 1798. Exhibiting a concife View of the latest and most important Difcoveries in Medicine and Medical Philofophy. By Andrew Duncan, Sen. M. D. and Andrew Duncan, Jun. M. D. &c. Vol III. Svo. 7s. Boards. Robinsons. 1799. ·

THE medical books analyfed in the firft part of this volume, are works of importance, fome of which have already occurred in our journal: the others we now proceed to notice.

Of Von Humboldt's experiments on ftimulated mufcular and nervous fibres, publifhed at Berlin in 1797, a minute and fatisfactory account is given. The fubject of that author's refearches is the fource of irritation, known by the name of galvanifm. This principle he examines in a very extenfive manner; and he has added to our knowledge of its mode of action, but without clearly explaining its nature. In order to vary his experiments at a lefs expenfe, he employed alkalis and oxy-muriatic acids, to excite and increafe irritability; and, occafionally, he ufed the common acids and the excels of ftimuli to lower it. This nearly coincides with their effects on the human body. Whatever may be found tree of the principle of galvanifin, its cffects are wholly on the nerves; and this doctrine is ultimately of fervice, in elucidating the functions of the nervous fyftem. Our experimentalift found, that the communication of galvanin did not require a chain of metals, or indeed any continuous chain. Animal matter might form the circuit, and the communication might be preferved, even if this matter were not in actual contact: the animal matter produced alfo greater effects, when in contact with the mufcle, than with the nerve. Thefe circumftances, which are well fupported, might furnith fome uleful corollaries. They feem to reconcile the oppofite opinions of Fontana and

Cruickshanks, refpecting the union of nerves; for, in this way, though no actual union is obfervable, yet the powers of life and motion may be communicated by their juxta-position. Even the metals are not required to be continuous to produce this effect. Homogeneous metals will excite contractions, when, by the addition of any fubftance to one part, they are rendered unlike in compofition, polith, hardnets, form, or temperature. When heterogeneous metals, viz. thofe which contain carbone, are employed, the flighteft diffimilarity in any part of the chain of exciters is fufficient: the effect is confiderably increafed by the evaporation of a fluid fubftance from one of the exciters, and is greater in proportion to the rapidity of the evaporation. All fluids, except oil, conduct the galvanic ftimulus even oil in fluid foap is a conductor, though dry foap infulates. Metals and carbone conduct; but, when united with oxygen and hydrogen, they are not conductors. Heat does not alter the conducting power of metals, or the infulating power of wax and fulphur; but water infulates both in the fate of ice and fteam. The epidermis of a vegetable infulates; but vegetables, when ftripped of the fkin, conduct the galvanifm, though weakly, and in an inferior degree to the dryeft animal matters. Teeth, when fet on edge' by an acid (a fenfation evidently connected with galvanifm), are conductors, but not in their natural fate. We will add our author's fynoptical table on this fubject.

Table of the power of substances to conduct the galvanic fluid.

• Conductors.

'Non-Conductors.

Metals. Sulphurated metals, and|| Oxyds of Metals. Sulphats of ores containing unoxydated metals, and ores containing oxydated metals.

metals. Carbon. Vegetable and mineral All Stones not containing carbon. coal, black lead, Kohlenblende.|| Animal Bones in their natural Touchstone, from the Nailaer state.

mountains. Schiftus alumi-|| Animal Hair.

naris and carbonarius; grey The hardened White of Egg•
and black ores of manganefe. Amber.

Mufcular Fle. Animal mem-
branes, nerves, finews, and
velfels; fresh, roafted, boiled,
and dried.
Teeth, fet in edge by means of Oil, Refins, Gums.

Leaves and Stalks of Vegetables,
covered with the epidermis.
Veffels of Plants.

acids.

Wax.

Glafs, even warm.

Morels, and Mushrooms, which|| All Dry Salts.

undergo the putrid fermenta-All Elaftic Fluids, dry and me

tion.

Flame.

Some perfons are infenfible to galvanifin, and fome are equally fo to the fhock of the electric eel. The effects of galvanism are fenfible through a chain of 300 feet, without any perceptible time loft in the paffage; and its influence, through this extent, is as obvious, as if the nerve continued entire, provided its coating be immediate.

M. Humboldt more particularly confiders the circumstances in which fresh animal matter will excite galvanism, and ascertains the greatest distance, at which he has been able to produce contractions, to be five fourths of a Paris line. The power of exciting it he fuppofes to belong to the feparated portion, as the excitability is only increased by wathing this part with the oxy-muriatic acid. This active atmosphere, however, is more confpicuous around muscle than around nerve; and it acts only on nerve; for, when the latter is feparated, it does not affect the muscle.

Galvanism is increased, when it is performed in oxy-muriatic gas; and it is diminished in carbonic acid gas. The actions produced by it are weaker in rarefied, and more active in condenfed air. It has no effect on vegetables. Fifh are violently convulfed by it. In birds, its phænomena are very tranfitory. In men, it excites the circulation, and produces inflammation, increafed difcharges, &c.

The different theories fuggefted for the explanation of thefe appearances are noticed. To us they are not fatisfactory; and we ftill think the phænomena of an electrical nature. The conditions neceffary to their production are afterwards explained. M. Humboldt is of opinion, that all the phænomena depend on the obftruction given to the galvanic fluid by imperfect conductors, and that, when accumulated in animal organs, it paffes more eafily through animal matter, than through metals, and with greater eafe through homogeneous than through heterogeneous metals.

Reil's Exercitationum Anatomicarum Fafciculus primus de Structura Nervorum' was publifhed at Halle in 1796. We must advert chicfly to the new doctrines which he broaches. The neurilema, or the proper coat of the nerves, is represented as an independent organ, not arifing, as has been supposed,

from the pia mater or any other membrane. It is said to determine the organisation of the nerves, and to be contracted or expanded, according to the degree of nervous energy required; to be tubulous and filled with medulla; ceafing, where the nerves arise from, or terminate in, the brain and its appendages. This coat is largely supplied with lymphatic and fanguiferous veffels, and is firm and elaftic, particularly in living animais. When a portion of a large nerve is feparated, its chords are found to be of various fizes, compofed of this proper coat,' filled with medulla; but, in general, when expanded in the organs of fenfe, the nerve lofes its tubulous ftructure, and becomes a cellular or spongy substance: in other words, this firm elastic coat is no longer fenfible. The medulla then is depofited from this coat, or rather from its veffels, and does not depend on the brain. The chords are ufually largest in the middle of a nerve, and become fmaller at its extremities: the nerves are fentible at each of their extremities, and the true nervous fibrils, contained in the neurilema, are of various fizes, frequently anaftomofing. The nerves our author thinks are fubject to inflammation; and he found the nerves of a man, who died of a typhus, remarkably turgid with blood. We have feen this appearance in the brain from a fimilar disease. Nervous action Dr. Reil confiders as a chemico-animal procefs arifing from a change in the chemical mixture of the medulla; and the numerous blood-veffels, contribute, in his opinion, to this compofition and decompofition of the medullary fubftance. The nerves themselves, befides their common functions, are fuppofed to affift in nutrition, in the production of vital heat, and in the chemico-animal procefs, in which life confifts. Their fphere of action is fuppofed to extend beyond their actual prefence.

M. Portal's work Sur la Nature et fur le Traitement de Rachitifme' is rather a treatife on chronic weakness from different causes, and has little connexion with the difeafe known by us under the term rickets. Perhaps his title implies no more, and the proper translation of rachitifme' is rachitic affections; but the work itself appears of no great importance.

6

M. Semering's paper On the Organ of the Soul' is extracted from Dr. Reil's Archives of Phyfiology. His great object is to prove, that all the nerves terminate in the ventricles of the brain, which naturally contain a fluid; and of courfe, as Sterne once ludicrously obferved, in thefe ventricles the foul refides in the ftate and dignity of a tadpole.

A paper, by M. G. Fifcher, is on the air-bladder of a fish. After an account of the different opinions of authors, he concludes, that it is an organ defined to decompote water, for the purpose of affording oxygen to the animal. We now know, not only that fish require air, but that all animals want a fup

ply of pure air; and therefore our author's opinion is probable, Oxygen has certainly been found in the bladders of fish. Azo tic and carbonic acid gas, however, are more frequently difcovered; nor will our author's fyftem avail him in the explanation of their appearance. He confiders these gaffes as the excrementitious remains of the decompofed water; but hydrogen is never found in the air-bladder, though, if this caufe were admitted, it would be the moft copious ingredient. On the whole, the ufe of this organ is ftill little known; and the opinion which we once offered is as probable as any other; viz. that it is the reservoir of the useless and excrementitious airs, for the purpose of increafing the buoyancy of the animal, in its native element.

In an account of fome trials, originally propofed by Dr. Chiarenti of Florence, we find that he fuppofed medicines often to difagree from their not being diffolved, in confequence of the vitiated ftate of the gaftric fluid, and propofed introducing them into the fyftein, ab extra, by abforption, after mixing them by rubbing with the gaftric juices. Trials were made with opium, fquills, and fox-glove, and thefe, when mixed with the galtric fluid, were found, by friction on the fkin, to produce their peculiar effects. Dr. Brera fupports and extends this plan by the authority and experience of many of the Italian profeffors and practitioners. When united with faliva, the medicines are faid to be equally efficacious. Dr. Chiarugi fupports the fame doctrine, with respect to opium in mania; but he employs axunge only in his preparation.

M. Marabelli's analyfis of the yellow bark fhows it to be an active kind of cinchona: but this author adds nothing to our pharmaceutical knowledge of its treatment. He adds little alfo to our knowledge of the chemical nature of the zea mayz, in his analytical difquifition on this fubject. Its large proportion of amylaceous matter and of animal gluten was well known.

In the urine of an icteric perfon, the fame author thinks, that bile was not contained, unlefs greatly changed, for it loft its bitter tafte by becoming putrid, and by evaporation. Befides, bile, diffolved in alcohol, was not decompofed by adding water, while the fpirituous folution of the jaundiced urine became milky on the affufion of water. Thefe facts prove only that the bile is changed by fecretion through the kidneys, which might eafily, a priori, have been fuppofed. In fome fpecies of diabetes, ftyled, from the want of a faccharine tafte in the urine, infipid, our author obferves, no fugar is contained; and of courfe he eftablithes the existence of this fpecies in oppofi tion to the mellitus.-The milky effufions, as they have been called, particularly in puerperal cafes attended by peritonitis, the fame author obferves, are not of a milky nature, but more nearly purulent. In this refpect, however, the experiments are not fatisfactory. The comparative trials were not