It is now only needful to say that modern anatomy and physiology afford aids to sound deductions in natural theology in reference to the structure of the human body as an animal organism, and all the functions of its different organs, which immeasurably transcend all that was known or assumed among the early Greeks, or in the time of Plato and Aristotle, or in the time of Galen. Notwithstanding the dispute whether the origin of man as an animal is to be referred to a special act of creation, or to the process of what has been called evolution, there can be no controversy on one point, namely, that modern anatomy and physiology have vastly increased our knowledge of the structure of the human frame, and the means of rational speculation upon the nature of intellect, as compared with any means that were possessed by the most accomplished and learned of the Greeks of antiquity. It matters little on which side of the controversy, between creation and evolution, the great anatomists of the present day range themselves. It is upon the facts which their investigations have revealed that we have to judge of the probable truth of the one hypothesis or the other. The probable destiny of man as an immortal being is an inquiry that has certainly lost nothing by our increased knowledge of the facts in his animal structure which tend to support the hypothesis of design in his creation. Lord Macaulay attributes an utter failure to the efforts of the philosophers, from Plato to Franklin, to "prove" the immortality of the soul without the help of revelation. What did he mean by proof? Revelation is, of course, the only direct proof. It is so, because it is direct testimony of a fact, proceeding from the only source that can have direct and certain knowledge of that fact. When the evidences which are supposed to establish the existence and authority of the witness have become satisfactory to us, we are possessed of proof of our immortality, and this proof is the only direct evidence of which the fact admits, and it constitutes all that should be spoken of as proof. But there is collateral although inferior evidence--inferior, because it consists in facts which show a high degree of probability that the soul of man is immortal, although this kind of evidence is not like the direct testimony of a competent witness. Is all this presumptive evidence, with its weighty tendency to establish the probable truth of immortality, to be pronounced of no value, because it belongs to a different order of proof from that derived from the assertion of a competent witness to the fact? It is one of the advantages of our situation in this life, that the collateral evidence which tends to show the high probability of a future state of existence is not withheld from us. As a supplemental aid to the direct teaching of revelation, it is of inestimable importance if we do not obscure it by theories which pervert its force, and if we reason upon it on sound philosophical principles.