• In a subsequent' part of' the Work, he ltditiortaa establish the identity of sensibility sot• irritability, or, at least, the ititimeto COMettlott which aphelia* between them, 'and the dependence of bah umbilici immediate and direct' operations of the vital thin He endeisvotatr to prose, that both the sena: tivb moving powers are eitereised•in. she Maus lifting fields of the body ; and adduces, insutiptirt of this !opinicin, Inouye the trgmieme browgirforward by Mt Hunter in prat` of the spititfity of the Moab On the 'subject of secrettott, issItligpreeeisla obit* Male been 1,ltlteltti 419/0100Eld• illitalkadli *Abe* and of which the explanation has in vain been sought for on mechanical and chemical principles, he is very brief ; as it is the peculiar adiantage of his theory, like the sword of Alexander, to cut through every knot that bids defiance to ordinary powers of unravelling. Secretion, being inexplicable by any of the hitherto known laws of nature, is, of course, simply the effect of the vital principle. The phenomena of animal heat were in danger of being at once consigned to the same Proteus-like power, which could operate every possible diversity of fdcts. But chemistry had, in this instance, inter posed some plausible theories, which must first be set aside ; and Barthez is at great pains to state the reasons of, his dissent from the received doctrines on this subject, and of his disbelief in the existence of caloric. He prefers the hypothesis which supposes heat to be a mere quality, excited by motion ; and generated accordingly, in living animals, by the in testine motions of their fluids, and the friction of the , solids against each other ; and the cause of these motions and frictions being unknown, it followed, as a necessary consequence, that they must arise from the operation of the vital principle. Respiration he considers as a cooling or moderating'process, and as useful, also, in exciting throughout the system the tonic actions ; but all these actions and agitations of the fibres, and these intestine motions of the fluids, are still regulated by the vital principle, which adapts them to variations of climate, and other external cir cumstances of temperature.
Amidst these vague and unprofitable speculations, his work contains a great store of facts, which are often instructive, though sometimes they expose the credulity of the author. He has collected, for ex ample, a number of curious particulars relative to the operation of different poisons on different animals; but intermingles with these well attested facts, many idle. tales respecting the bites of rabid or enraged animals, in which the peculiar manners of the ani mal were communicated to the human species. Thus, he 9uotes instances of men barking or attempting to bite in hydrophobia ; of some mewing like cats, after having been bitten by these animals ; and of others, again, who flapped their arms, and crowed like cocks, after receiving the bite of one of these birds.
A large portion of the work is dedicated to the consideration of Sympathies, which he distinguishes from what he terms Synergies; defining the latter to be the connection, whether simultaneous or suc cessive, of the vital forces of different organs, so as to constitute a function or a disease. He divides sympathies into three classes, according as they occur between organs having no visible relation to each other, those which have similar structures and functions, and those which are united by an inter mediate texture, or by receiving the same set of vessels or nerves. His chapter on-Temperaments is
ably drawn up ; and be discusses well the compara tive influence of physical and moral causes in modi fying the human temperament, and the changes pro duced by age, and the approach of death. He ex plains the operation of the more usual causes of death ; and enters into a comparison of the mutabi lity of different seasons and climates ; and concludes, from several facts and arguments, that the actual cessation of life is, in general, not accompanied by any painful sensation.
The merit of Barthez, as a physiologist, is more conspicuous on subjects which admitted less of his being led astray by his proneness to indulge in ab stract speculation, and his predilection for meta physical refinement. The most favourable speci men of his talents is afforded by his Nouvelle Mi chanire des Mouvemena de r Honitne et des .4nimauz ; in which, avoiding all discussion as to the cause of muscular motion, he traces the mode in which this force has been applied by nature, according to the principles of mechanism, in effecting the different movements of the animal machine. He examines the relative disposition of the bones and muscles, the structure of the articulations, and the general play and particular motions of the limbs. Borelli (Dc Motu Anitnalium) bad given the first model of such a work ; but Barthez has investigated the subject with greater care, and has extended his views to a much wider range of phenomena. He enters mi nutely into the consideration of a great variety of modes of locomotion, both in man and the inferior animals ; for which he has amassed an immense number of facts ; forming, altogether, a work which will ever remain a monument of his industry and su perior abilities.
In consulting his writings on the practical branches of his profession, we again find ourselves bewildered in a labyrinth of speculations on the proximate causes of disease, and the modus operandi of remedies. In his Treatise on Gout, he adopts the principles of the humeral pathology, in addition to his own phy siological doctrines concerning the force of fixed situation, or principle which retains muscular parts in their appropriate places independently of irritabi lity. He states the proximate cause of this disease to be a specific gouty state of the habit ; which he infers from the supposed influence he has observed from specific remedies, and especially aconite, in curing it. He defines the gouty state of the blood to consist in " an improper mixture of its component parts, which prevents, in different degrees, the natural formation of its excrementitious humours; so that these humours, being more or less altered, undergo a spontaneous decomposition, which causes the earthy substance to predominate in them." This earthy substance, or, in other words, gouty matter, is deposited upon the extremities, and thus occasions the paroxysm. His practice, on the whole, notwithstanding his adoption of theories now gene rally exploded, is tolerably judicious ; though he shows but little discrimination in the analysis which he gives of the works of practical authors on this dis ease ; and he seems to be strangely deficient in • in formation as to the practice of English physicians. In other respects, his knowledge is accurate and co pious ; and the history he gives of several of the ir regular forms of gout, and also that of sciatica, in which, however, he 'chiefly follows Cotannius, are deserving of praise.