6. Lile is a forced state, and consequently its conti nuance in perfection depends on the due action of the stimuli on the excitability. Health, then, is maintained by the exertion of natural stimuli on the excitability.
7. But whenever they are unnatural, or act with too much energy, the excitability is exhausted, and the ex citement becomes greater than it ought to be. This is a state to which Dr Brown gave the name of sthcnic dia thesis, which predisposes to sthcnic disease. This dia thesis, or predisposition, may be increased very conside rably by injudicious management.
3. After excitement has been carried to its utmost pitch, it ends in indirect debility, which gives rise to asthcnic diseases.
9. Indirect debility is induced by the excessive ac tion of stimuli, or by their too great intensity. The ex citability is then supposed to be exhausted.
10. Direct debility, is, on the contrary, induced by a defect in the stimuli, or by their feeble action.
I I. These two species of debility differ most essen tially, and are sufficiently characterized. They t xist in health as well as in disease. Indirect debility occurs in old age, and direct debility in youth or infancy.
12. Sleep is the effect of both kinds of debility, either separate or conjunctly.
13. Every power that acts on the living frame is sti mulant. This principle is supposed not to be affected by any circumstances whatever.
1.1. Excitability exists in the medullary portion of the nerves and in the muscles. It sympathises in every part of the system. That is, different parts can never be in opposite states of excitement.
Dr Brown contrived two scales, the first of which he divided into 80 degrees, sliming the quantity of excita bility given to every being at the commencement of its existence. The second "points out the ascending and
descending progression which the exciting powers ob serve in acting on the excitability." Such are the outlines of the system of Dr Brown. With all its ingenuity we must still hesitate in adopt ing it, until we can obtain something more than the blending of some truth with much conjectural hypothe sis. We dislike the phraseology, and still more the arrogance, with which both the author and his followers have asserted their infallibility.
Still, however, it cannot be denied, that some of the conclusions have proved more useful than was at one time expected.
It, fortunately, is a matter of very little moment, how physicians theorise. Few, even the devoted disciples of Dr Brown, would follow the example of that gentle man, and venture on prescribing wine, high living, and opium, in gout. The use so liberally made by Brown and his proselytes of the term demonstration, as applied to the doctrines above sketched, cannot fail to excite the ridicule of those who, from having attended to the na ture of medical inquiries, have been convinced that doubt and obscurity must overshadow every step of the physiologist and physician, until certain fundamental facts be ascertained, which the present faculties of man kind are not likely to developc. Sec Brown's Writings and Lift., by Dr Beddoes ; and The Works of Dr John Brown, with a Biographical Account of the Author, by William Cullen M.D. (c. /%1.)