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Notes on the lectures of Dr. John Syng Dorsey professor of materia medica in the university of penn. Vol. II Nov. 7th 1817. 2nd Lecture. In commencing my lectures on the mat. med. gentleman, I need not inform you, that the chair has heretofore been filled by men of hte most distinguished talents. In teaching the branch to which I have been appointed, I shall make every exertion to be useful to you; I am well appraised that all that a teacher can do is to judiciously conduct you to a knowledge of the elements. The mat. mid has for its objects an acquaintance with every thing that preserves and supports life. Of these, it is highly [necessary] that the student should be informed. I propose to pursue the plan of my able [predecepor], discriminating between what is useful and superfluous, rejecting the latter and giving you the former, in order that you may become good practitioners. We shall commence our lectures with the subject of animal life. Dr. Johnson defines life to be the union
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Animal life
of soul & body. This def seems to be very obscure but we must not forget the difficulty often attending deefinitions. I shall define life to be a power of resisting putrefaction & chemical changes or processes, & of perserving the system in a temp. different from that of the atmosphere. Among many, the phenomena of life as exhibitted in motion,-heat-, sensation,& thought have been said to constitute life. This doctrine has had many advocates, Dr Rush taught it & before him Dr Brown. This we consider completely refuted by the fact that life may exist without its phenomina. Fish when frozen for some time are not dead yet all the phenomena of life are absentVitality is as perfect in plants as in animals and in the oyster as in man. By [??] Brown Rush & others, life has been ssaid to be a parced state, but none of them are the authors of it for Dr Cullen taught it as early as 1766 in the university of Edinburg. Stimuli can never create life. They say
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Animal Life a capacity for life exists, but the capacity for it, is life. Most of the actions of life are the effects of stimulants, as sound on the ear, light on the eye, et cet. Can any vital action take place without the agency of stimulants? The actions of life are forced, but the powers of life are not forced. We might as well say that the air makes flame when we burn carbon. Tis impossible to produce life in dead matter, by the action of stimuli. If you take two fishes, one frozen dead, the other alive, by applying heat to both, the former will suffer putrefaction, and the latter will not. Next we may inquire whether or not organization influences life? Among the lower classes of animals the organization is very simple. In the Hydatid and [polypus], we have examples. The Hydatid is extremely simple in its organization, it probably exists of nothing but a stomach and absorbants, and digestion constitutes its only function. The doctrine that the blood [possesses] life has been defended by Mr. J. Hunter. Where we consider
