[2]. Humboldt, op. cit., p. 386. In his Aphorismi ex doctrina Physiologiæ chemicæ Plantarum, appended to his Flora Fribergensis subterranea, published in 1793, Humboldt had said “Vim internam, quæ chymicæ affinitatis vincula resolvit, atque obstat, quominus elementa corporum libere conjungantur, vitalem vocamus.” “That internal force, which dissolves the bonds of chemical affinity, and prevents the elements of bodies from freely uniting, we call vital.” But in a note to the allegory above mentioned, added to the third edition of the Views of Nature in 1849, he says: “Reflection and prolonged study in the departments of physiology and chemistry have deeply shaken my earlier belief in peculiar so-called vital forces. In the year 1797, * * * I already declared that I by no means regarded the existence of these peculiar vital forces as established.” And again: “The difficulty of satisfactorily referring the vital phenomena of the organism to physical and chemical laws depends chiefly (and almost in the same manner as the prediction of meteorological processes in the atmosphere) on the complication of the phenomena, and on the great number of the simultaneously acting forces as well as the conditions of their activity.”
[3]. Compare Henry Bence Jones, Croonian Lectures on Matter and Force. London, 1868, John Churchill & Sons.
[4]. Ib., Preface, p. vi.
[5]. Rankine, W. J. M., Philosophical Magazine, Feb., 1853. Also Edinburgh Philosophical Journal, July, 1855.
[6]. Armstrong, Sir Wm. In his address as President of the British Association for the Advancement of Science. Rep. Brit. Assoc., 1863, li.
[7]. Grove, W. R., in 1842. Compare “Nature” i, 335, Jan. 27, 1870. Also Appleton’s Journal, iii, 324, Mch. 19, 1870.
[8]. Id., in Preface to The Correlation of Physical Forces, 4th ed. Reprinted in The Correlation and Conservation of Forces, edited by E. L. Youmans, p. 7. New York, 1865, D. Appleton & Co.
[9]. Id., ib., Am. ed., p. 33 et seq.
[10]. Joule, J. P., Philosophical Transactions, 1850, p. 61.
[11]. See American Journal of Science, II, xxxvii, 296, 1864.