In the same manner that Mr. McLean argues with regard to disease, let us argue concerning bodily strength. Some men are able to lift a weight of 6 or 700 pounds, but a great majority cannot lift above 300. Whence proceeds the difference? Is it the few who lift the great weight that _by nature_ have _more_ strength, or is it the many who can lift only the smaller that _by nature_ have _less_? This is precisely his argument, and there needs no other refutation than stating it in this manner. What he calls the states of excitability are as much _idiosyncrasies_ at the time as any thing else. Mr. McLean will not deny that a person debilitated by certain causes is more liable to be seized with typhus fever than one who is not. What does this proceed from, but that the body of the one is prepared for the disease, is _constitutionally_ disposed to receive it, or has an _idiosyncrasy_ of habit disposing to it, which the other has not? It is true, that unless we point out the circumstances which constitute this idiosyncracy we do nothing; but Mr. McLean’s scheme, of resolving every thing into _excitability_, would forever prevent us from doing so. This is the great deficiency of the Brunonian system altogether; for, by attending only to the animal life of the body, he seems to have absolutely forgot that we had any thing in common with vegetables. The bones, for instance, or indeed any part of the body, cannot be formed by the power which governs it after it was formed. The growth of the human body is as strict vegetation as that of a tree; and therefore we find that after the excitability is entirely gone, after death has taken place for a considerable time, the body still retains its form, and would do so forever, did not other powers interfere with it. Human life therefore is a compound of the vegetable and animal life, the former being the basis of the latter; and it is the vegetable life which is much more commonly the subject of disease than the animal life. In vegetables we observe an _idiosyncracy_ of habit, as well as among animals. Some, even of the same species, are much more vigorous than others, and, among some, diseases are much more common than others. In like manner among the human race some are strong, others weak; in some the blood is much more confident, and coagulates on exposure to the air much more firmly than in others. Excitability, or excitement, is common to all, and the degrees of it (though enumerated by Yates and McLean in a kind of thermometrical scale) must be merely imaginary, because excitability is not the object of our senses. The obvious properties of the body itself, independent of any excitement whatever, are principally to be considered in medicine. These constitute the peculiar constitution, or the _idiosyncracy_ of habit, belonging to each individual. Yet, in defiance of every confederation of these obvious properties, which all have access to observe, the new system