As speculations concerning the origin of matter lie without the domain of natural or scientific inquiry, they form no part of the investigations of the naturalist. So far as is known, matter is eternal, and all that may be learned concerning it must be gleaned by observing the changes, chemical and molecular, through which it is manifested. By those who have observed the laws which govern the manifold changes in matter, the fact is declared that the various manifestations in form and substance constitute the only creation of which we may have any knowledge; and, moreover, that the genesis of existence is going on as actively in our time as at any previous period in the history of matter. So far as human knowledge extends, no particle of matter has ever been created and none ever destroyed. This continuous process of transmutation of substance and change of form, in other words the phenomena designated Life, may have been in operation during all the past, and may continue forever. As all speculations concerning the origin of matter have been unavailing, so all attempts to solve the problem of the origin of life have proved futile. The experiments recently carried on in the Rockefeller Institute, in which by means of chemical processes detached organs from the bodies of animals have been made to perform their normal functions, are interesting and instructive, but these experiments furnish no clue to the origin of the force which animates living organic matter. Why the nucleated cells which we call a heart should pulsate whilst those which we call a liver should secrete bile, nobody knows. That all life on the earth has been derived from one, or at most from a few original forms, is said to be proved by ontogeny, or the history of the germ, which in its development passes through a number of the forms which mark the ascending scale of life. Through the study of comparative anatomy, the fact has been discovered that the individuals composing the various orders of the great vertebrate series are all moulded “on the same general plan”; that up to a certain stage in the development of the several germs—for instance those of the man, the ape, the horse, the dog, etc.,—they are not distinguishable the one from the other, and that it is only at a later stage of development that they take on the peculiarities belonging to their own special kind. The number and variety of forms which appear in the animal and vegetable world make it difficult to conceive of the idea that all have sprung from one, or at most from a few original types, yet the chain of evidence in support of this theory seems quite complete.