_Per contra_, see the Address of Dr. F. A. P. Barnard, as retiring President, before the Am. Assoc. for the Advancement of Science, Chicago meeting, August, 1868. “Thought cannot be a physical force, because thought admits of no measure.” GOULD, BENJ. APTHORP, Address as retiring President, before the American Association at its Salem meeting, Aug., 1869. BEALE, LIONEL S., “Protoplasm, or Life, Matter, and Mind.” London, 1870. John Churchill & Sons. Footnote 37: For an excellent account of this distinguished man, see Youmans’s Introduction to the Correlation and Conservation of Forces, p. xvii. Footnote 38: DRAPER, J. W., _loc. cit._ Footnote 39: HENRY, JOSEPH, Agric. Rep. Patent Office, 1857, 440. Footnote 40: WATTERS, J. H., An Essay on Organic, or Life-force. Written for the degree of Doctor of Medicine in the University of Pennsylvania, Philadelphia, 1851. See also St. Louis Medical and Surgical Journal, II, v, Nos. 3 and 4, 1868; Dec. 1868, and Nov. 10, 1869. Footnote 41: LECONTE, JOSEPH, The Correlation of Physical, Chemical and Vital Force, and the Conservation of Force in Vital Phenomena. American Journal of Science, II, xxviii, 305, Nov. 1859. Footnote 42: LOMBARD, J. S., _loc. cit._ Footnote 43: NOYES, T. R., _loc. cit._ Footnote 44: WOOD, L. H., _loc. cit._ ------------------------------------------------------------------------ _AS REGARDS PROTOPLASM, ETC._ ------------------------------------------------------------------------ PREFATORY NOTE. The substance of the greater part of this paper, which has been in the present form for some time, was delivered, as a lecture, at a Conversazione of the Royal College of Physicians of Edinburgh, in the Hall of the College, on the evening of Friday, the 30th of April last. It will be found to support itself, so far as the facts are concerned, on the most recent German physiological literature, as represented by Rindfleisch, Kühne, and especially Stricker, with which last, for the production of his “Handbuch,” there is associated every great histological name in Germany. EDINBURGH, _October, 1869_. ------------------------------------------------------------------------ AS REGARDS PROTOPLASM, ETC.