[29] Analysis of the Phenomena of the Human Mind. By James Mill. Edition of 1869, with Notes by Alexander Bain, Andrew Findlater, George Grote, and John Stuart Mill, vol. i. pp. 78 _et seq._ [30] Mill's 'Logic.' 5th Edition. Vol. i. p. 377. [31] 'There is a class of animals called Ascidians, which possess a heart and a circulation, and up to the year 1824 no one would have dreamt of questioning the propriety of the deduction, that these creatures have a circulation in one definite and invariable direction; nor would any one have thought it worth while to verify the point. But in that year M. von Hasselt, happening to examine a transparent animal of this class, found to his infinite surprise that after the heart had beat a certain number of times, it stopped, and then began beating the opposite way, so as to reverse the course of the current, which returned by-and-by to its original direction.'--_Huxley's Lay Sermons_, p. 95. CHAPTER IV. _HUXLEYISM._ '_A force d'esprit tout lui paroit matiere._' In one of his interesting 'Lay Sermons,' the most interesting perhaps of the whole interesting series, Professor Huxley, taking for his theme the 'Physical Basis of Life,' combats 'the widely-spread conception of life as a something which works through matter, but is independent of it;' affirming, on the contrary, 'that matter and life are inseparably connected, and that there is one kind of matter which is common to all living beings.' The preacher may be safely allowed to have satisfactorily made out the second portion of this affirmation. With his own singular felicity of illustration, he shows how all vegetable and animal tissues, without exception, from that of the brightly coloured lichen looking so like a mere mineral incrustation on the rock that bears it, to that of the painter who admires or the botanist who dissects it, are, however diverse in aspect, essentially one in composition and structure. He explains how the microscopic fungi clustering by millions within the body of a single fly, the giant pine of California towering to the height of a cathedral spire, the Indian fig-tree covering acres with its profound shadow, the animalcules of ocean's lowest deep, minute enough to dance in myriads on the point of a needle, and the Finner whale, hugest of beasts, that disports its ninety feet of bone and blubber on ocean's billowy heights, the flower that a girl wears in her hair, and the blood that courses through her veins, are, each and all, smaller or larger multiples or aggregates of one and the same structural unit, which, again, is invariably resolvable into the same identical elements. That unit, he tells us, is an atom or corpuscle composed of oxygen, nitrogen, hydrogen, and carbon, which, and which alone, seem to be required by nature for laying withal the foundations of vitality, inasmuch as no substance from which any one of these ingredients is totally absent, ever exhibits any sign of life,