satisfactory answer to this question. Not I, certainly. All what with certainty can be said, is that such movements are part of the usual course of Nature, inasmuch as they still take place before our eyes. It can be safely proved that some parts of the land of the northern hemisphere, is at this moment insensibly rising, and others insensibly sinking; and it can be shown indirectly but sufficiently, that a vast area which now is covered by the Pacific ocean, has deepened thousands of feet since the present inhabitants of that sea came into existence. Hence, there is not a shadow of reason for believing that the physical transformations of earth, in past times, have been effected by other than natural

causes.

Is there more reason that the accompanying transformations of the living inhabitants of the planet have been brought about in another manner? Before I answer this question, let me report a special case. The crocodiles have, as a group, a high antiquity. They were there in abundance before chalk was deposited; today they crowd in the rivers of hot countries. There is, certainly, a difference in the shape of the joints of the spine, and in some smaller particulars between the crocodiles of the present time and those of the chalk period; but, as I remarked before, they assumed, in the later, the modern type of their structure. Nevertheless

the crocodiles of the chalk period are not identical with those which lived in the older tertiary period (as they call it) which followed that of chalk; and the crocodiles of the older one are not conform to those of the newer tertiary period, nor are these identical to the still living forms. Every epoch had its own crocodiles. How can the existence of such a long series of different species of crocodiles be explained? It seems there are

only two suppositions either every species of crocodiles was, especially created, or it developed from some form which before had existed by the activity of natural causes. Choose your hypothesis; I have chosen mine. I can find no warranty for believing in the distinct creation of a score of successive species of crocodiles in the course of countless ages of time. Science does not support such a wild production of imagination. On the other hand, I see no good reason against the acceptance of the other hypothesis that all these various species have been developed from pre-existing crocodilian forms by the efficacy of causes as completely a part of the common order of Nature, as those which have effected the changes of the inorganic world.

Few will venture to affirm that the reasoning which applies to crocodiles, looses its force among other animals, or among plants. If one series of species has come into existence by the operation of natural causes, it seems folly to deny that all may have arisen in the same way.

A small beginning has conducted us to a great end. If I should throw the small piece of chalk with which we began in the hot but dark flame of burning hydrogen, it would presently shine like the sun. This physical metamorphosis seems to me to be an image not badly chosen for the nature of a lecture. It has illuminated the obscure abyss of passed times, and brought some studies of the development of the earth into the clear horizon of our intuition. And in the shifting "without haste but without rest," of land and sea, as in the infinite variation of the forms assumed by living beings we have observed nothing but the natural product of the forces which the matter of the Universe possessed at all times.

VOICES OF SCIENCE ON SOME TENETS OF MATERIALISM.

There are truths which, in modern time, are asserted by scientific men, but give offense to many of our COtemporaries, and excite their doubts, because they contradict adopted prejudices. It is the purpose of the following communication, to propose some of these truths to the thinking reader, or, if he knows them already, to recall them to his mind. But I intend to propound them by the very words of those men who pronounced them in their writings, though to much vexation of biased ones. I commence with the sentence of the English naturalist, Thomas Huxley: "All organic shapes of formation are identical in their elements." He writes in his book "Lay Sermons," in this way:

IDENTITY OF THE ELEMENTS OF ALL ORGANISMS.

"What is organic nature? Nature which possesses life; therefore all animals and, plants belong to its realm for modern botany attributes life also to plants; the terms organic and living nature are synonyms. All organic beings commence their existence in the same form, namely the form of an egg or cell.—If you reduce an oak, or a man, or a horse, or an oyster, or any other animal to their first germs: you will see that all begin their existence in forms which essentially resemble each other, and, besides, you will observe that the first steps of growth and many of their later transformations, almost all follow, essentially, the same principle. These sentences are not mere hypotheses; they can be as well demonstrated, as the theorems of geometry and arith

metic; they rest on facts, on which Darwin founded his theory of the origin of species, and which are confirmed by "all great natural philosophers of our time."

From this theory of the great English naturalist which by all men of natural science is approved, many other important theorems can be deduced, of which I will state a few.

THE FUNCTIONS OF MIND ARE A PRODUCT OF THE BRAIN.

If all organic shapes of formation are effected by Nature, the functions of human mind must also be a product of Nature. There are many natural philosophers, who consider these functions as a product of the brain. Instead of proving their opinions myself, I will give again the words of men who are celebrated by their scientific culture. Karl Vogt, (Physical Letters,) says: "It is nonsense to suppose a soul which uses the brain like an instrument; or you must also suppose a special soul for every function of the body." Moleschott (circulation of the blood) writes: "The brain is to the production of thoughts quite as necessary, as the liver for the preparation of the bile." And Louis Buchner (Kraft and Stoff) says: "The brain and soul are identical, or the brain is the cause of thought."

IS THE SOUL IMMORTAL?

If all forms of natural formation are variable, and liable to perish, the functions of mind must also have an end with the dissolution of the body. I quote again: "Under whatever disguise it takes refuge, whether fungus or oak, worm or man, the living protoplasm ultimately dies, and is resolved into its mineral and lifeless constituents." Huxley-"I object to affirm that I look to a future life, when all that I mean is that the influence of my sayings and doings will be more or less

felt by a number of people after the physical components of that organism are scattered to the four winds." The same:-"The soul is to the theology an incorporeal principle which lives in the body, and remains, when that one perishes. But it is not such a principle for natural science; if its organ, the body, perishes, the soul has also an end; science does not know an individual continuation of soul. Not only the times have been, that, when the brains were out the man would die, and there an end, (as Macbeth says): nowadays it is the same and it will be so forever." K. Vogt, (Physical Letters.) Bock, one of the most renowned German physicians, and professor in Leipsic, writes in the same way: "The materialist affirms that, according to immutable natural laws, also the mental force of the brain must cease, if its matter perishes." Again: "Mind being the result of organized nervous matter, is like the material man, subject to mortality."--Boston Investigator.-"The most painful truth/is death; how, then, should we acknowledge it? Therefore, we deny that death is the end of man; and still, this end is a truth quite as common, evidently testified by the senses, as man's birth, proved by the same witnesses, the senses, as his commencement."--Feuerbach. "The soul origi

nates with the brain, it grows, decreases and is taken ill with it; a lasting separation of both is impossible. There is no matter without force, and inversely. Mind cannot be imagined without a body, not more than electricity or magnetism or without metals. Soul did not exist for an eternity; if it were indestructible, it had to have existed for an eternity. That what once did not exist must also again perish."-Louis Buchner, (Kraft and Stoff., § 16.)

Moreover from the principle of Huxley follows:

If