to Stahl. It must, however, be sufficiently obvious, and I shall conclude the subject with observing, that although the vis medicalrix naturæ must unavoidably be received as a fact; yet, whereever it is admitted, it throws an obscurity upon our system; and it is only where the importance of our art is very manifest and considerable, that we ought to admit of it in practice.

To finish our remarks upon the Stahlian system, I shall shortly observe, that it did not depend entirely upon the Autocrateia, but also supposed a state of the body and diseases, that admitted of remedies, which, under the power and direction of the soul, acted upon the organization and matter of the body, so as to cure its diseases. Upon this footing, the Stahlian pathology turned entirely upon Plethora and Cacochymy. It was with respect to the former that they especially applied their doctrine of the Autocrateia in a very fanatical manner; and, with respect to the latter, they have been involved in a humoral pathology as much as the systematic physicians who had gone before them, and with a theory so incorrect as not to merit now the smallest attention. After all, I ought not to dismiss the consideration of the Stahlian system, without remarking, that as the followers of this system were very intent upon observing the method of nature, so they were very attentive in observing the phenomena of diseases, and

have given us in their writings many facts not to be found elsewhere.

While the doctrines of Stahl were prevailing in the university of Halle, Dr. Hoffman, a professor in the same university, proposed a system that was very different. He received into his system a great deal of the mechanical Cartesian, and chemical doctrines of the systems which had appeared before: but, with respect to these, it is of no consequence to observe in what manner he modified the doctrines of his predecessors, as his improvements in these respects were nowise considerable, and no part of them now remain; and the real value of his works, beyond what I am just now going to mention, rests entirely on the many facts they contain. The merit of Dr. Hoffman and of his work is, that he made, or rather suggested, an addition to the system, which highly deserves our attention. Of this I cannot give a clearer account than by giving it in the author's own words. In his Medicina Rationalis Systematica, tom. iii, § 1, chap. 4, he has given his Genealogia morborum ex turbato solidorum et fluidorum mechanismo; and in the 46th and last paragraph of this chapter, he sums up his doctrine in the following words: Ex hisce autem omnibus uberius hactenus excussis, perquam dilucide apparere arbitror, quod solus SPASMUS et simplex ATONIA, æquabilem, liberum, ac proportionatum

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sanguinis omnisque generis fluidorum motum, quibus excretionum successus et integritas functionum animi et corporis proxime nititur, turbando ac pervertendo, universam vitalem œconomiam subruant ac destruant; atque hinc universa pathologia longe rectius atque facilius EX VITIO MOTUUM MICROCOSMICORUM IN SOLIDIS, quam EX VARIIS AFFECTIONIBUS VITIOSORUM HUMORUM, deduci atque explicari possit, adeoque omnis generis agritudines internæ, ad PRÆTERNATURALES GENERIS NERVOSI AFFECTIONES sint referendæ. nim læsis quocunque modo, vel nervis per corpus discurrentibus, vel membranosis quibusvis nervosis partibus, illico motuum anomaliæ, modo leviores, modo graviores, subsequuntur. Deinde attenta observatio docet, motus quosvis morbosus principaliter sedem figere et tyrannidem exercere in nervosis corporis partibus, cujus generis præter omnes canales, qui systaltico et diastaltico motu pollentes, contentos succos tradunt, universum nimirum intestinorum et ventriculi ab œsophago ad anum canalem, totum systema vasorum arteriosorum, ductuum biliariorum, salivalium, urinariorum et subcutaneorum, sunt quoque membranæ nerveo-musculares cerebri et medulla spinalis, præsertim hæc, quæ dura mater vocatur, organis sensoriis obducta, nec non tunicæ illæ ac ligamenta, quæ ossa cingunt artusque firmant. Nam nullus dolor, nulla inflammatio, nullus spasmus, nulla motus et sensus impotentia, nulla febris aut humoris ullius ex

cretio, accidit, in qua non hæ partes patiantur. Porro etiam omnes, quæ morbos gignunt causæ, operationem suam potissimam perficiunt in partes motu et sensu præditas, et canales ex his coagmentatos, eorum motum, et cum hoc fluidorum cursum, pervertendo; ita tamen, ut sicuti variæ indolis sunt, sic etiam varie in nerveas partes agant, iisdemque noxam affricent. Demum omnia quoque eximiæ virtutis medicamenta, non tam in partis fluidas, carum crasin ac intemperiem corrigendo, quam potius in solidas et nervosas, earundem motus alterando ac moderando, suam edunt operationem: De quibus tamen omnibus, in vulgari usque eo recepta morborum doctrina, altum est silentium.

It is true, that Dr. Willis had laid a foundation for this doctrine, in his Pathologia Cerebri et Nervorum; and Baglivi had proposed a system of this kind in his Specimen de fibra motrici et morbosa. But, in these writers, it was either not extensively applied to diseases, or was still so involved in many physiological errors, that they had attracted little attention; and Dr. Hoffman was the first who gave any tolerably simple and clear system on the subject, or pointed out any extensive application of it to the explanation of diseases.

There can be no sort of doubt that the phenomena of the animal economy in health and

in sickness, can only be explained by considering the state and affections of the primary moving powers in it. It is to me surprising, that physicians were so long of perceiving this, and I think we are therefore particularly indebted to Dr. Hoffman, for putting us into the proper train of investigation; and it every day appears, that physicians perceive the necessity of entering more and more into this inquiry. It was this, I think, which engaged Dr. Kaaw Boerhaave to publish his work entitled Impetum faciens; as well as Dr. Gaubius to give the Pathology of the Solidum vivum. Even the Baron Van Swieten has, upon the same view, thought it necessary, in at least one particular, to make a very considerable change in the doctrine of his master, as he has done in his commentary upon the 755th aphorism. Dr. Haller has advanced this part of science very much by his experiments on irritability and sensibility. In these, and in many other instances, particularly in the writings of Mr. Barthez of Montpelier, of some progress in the study of the affections of the nervous system, we must perceive how much we are indebted to Dr. Hoffman for his so properly beginning it. The subject, however, is difficult: the laws of the nervous system, in the various circumstances of the animal economy, are by no means ascertained; and, from want of attention and observation with the view to a system on this subject, the business appears to many as an inexplicable mystery. There

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