[83] Ibid. "Scientific use of the imagination."
[84] Fragments of Science, "Spontaneous Generation."
[85] Ibid. "Rev. James Martineau and Belfast Address."
[86] Ibid. "Vitality."
[87] Nineteenth Century, May, 1886, p. 769.
[88] Italics mine.
[89] It has been established by Pasteur and others that the highest temperature at which organic life is possible is 45° Centigrade (113° Fahrenheit). When the globe had cooled to this point from its primitive molten condition, the epoch of terrestrial life commenced.
According to what is perhaps the latest theory, that of M. Quinton, the temperature immediately below this, 44° Centigrade, remains always the best for living things, and those creatures are highest in the scale of life, and consequently the most developed, which have contrived means of keeping their internal heat at, or about, this level, despite the refrigeration of their surroundings. In their blood-heat M. Quinton therefore finds an absolute rule for fixing the relative rank of organic forms, and the date of their appearance; those whose blood is warmest being the most recently evolved. The results of this new system are sufficiently startling. Birds are to be classed as the highest and newest of all; while man, with the other Primates, has to take a much lower place, the ungulates, including the horse and donkey, and the carnivora, as dogs and cats, being his superiors. (La Revue des Idées, January 15, 1904, pp. 29 seq.)
[90] To D. Mackintosh, February 28, 1882.
[91] To Sir J. D. Hooker, March 29, 1863.