What then exists now? I answer, first of all a vast chain of vegetable life, fitted in every portion of it to find its own subsistence, and to propagate its species. Its main function is to "manufacture out of mineral substances that protoplasm, upon which, in the long run, all animal life depends." (Lay Sermons, p. 138.) I need not detain you by enumerating the many various contrivances by which plants are enabled to manufacture food for us out of carbon, hydrogen, oxygen, and nitrogen--substances upon which, in their original state, animals cannot feed--nor the still more curious and elaborate processes by which their fecundation, and the propagation of each species is provided for--processes which seem often to require the intervention of animal life. I need not detain you upon this point: you will readily grant that this correspondence does exist. If a plant is not suited to its habitat, and cannot use its natural powers, nature imposes upon it the severe penalties--first, of degradation, and then of death. Upon the animal world she imposes just the same penalties. There is neither excess nor defect in her operations.[19] Whatever she gives must be used, but animals, being governed in the main by instincts, have no choice. They necessarily employ all their living powers, and apparently have no powers beyond those indispensable for their existence. This point, however, I will not press, though it seems to follow from the fact asserted by Professor Huxley, that no important difference can be observed between the fossil remains found in the earliest strata, and animals of the same species and order existent now. (See pp. 241, 242, and for vegetables, p. 240.) For, as he tells you, facts establish a scientific law--law in the mouths of scientific men, meaning an established order of facts. Well then! I will put this fact of absence of progress aside, and with it the corollary of the absence of latent powers.[20] But of actual powers it is evident that animals do use them all, and have to use them all. So close, too, is the agreement between the powers and the external position of every animal, that a change in its external relations will modify its powers to a certain extent. But only to a certain extent; there are fixed limits to the adaptability of those living powers. If the changes are such as to occasion a more active exercise of its living powers, the animal increases in strength, size, and beauty; if unfavourable, but still permitting some use of its powers, it dwindles and decays. But pass the appointed bounds and the animal dies. Nature is exacting the penalty of the non-use of what it has given. Nature exacts a severe penalty for the mis-use, and the last and final penalty for the violation of her laws. I do not know that an ascidian jelly-bag has any other faculties than those of sucking in water, and of sticking to a stone.[21] But this I know, that if it does not use all the powers it