accounts for the difficulty experienced in finding ready to hand general conclusions which have secured universal acceptance, when we begin to move somewhat freely over the wide regions presenting the manifold problems of organized existence. And as it is solely with general conclusions, that religious thought is concerned, some share of perplexity must attach to the attempt to discuss the question of harmony. We must here therefore be considerably involved in questions affecting theories which have gained wide favor in scientific circles, as well as with clearly recorded and certain results. Some general questions, such as that affecting the classification of animals, must be regarded as peculiarly scientific. Whether the classification of Linnæus, or of Cuvier, or some other more recently suggested, is to be preferred, is a matter which does not here concern us. But a theory of the origin of species must be considered, because it is not purely scientific, but brings science into direct relation with common thought as to the order of the universe, and may therefore stand related to religious thought. Immediately on directing attention to organized existence,--to LIFE in any form,--we encounter a new problem, namely the relation of the organized to the unorganized. How is the appearance of this higher order of existence to be accounted for? Can we find in the nature of matter, and in the mechanical and chemical laws influencing its position and combination, any explanation of the appearance of life in the world? Or must we regard life as a new and higher fact, unexplained by reference to the lower form of existence, and incapable of explanation in this way? Whether there is a clear line of demarcation between vegetable and animal life is a comparatively subordinate question. It is the wider and more perplexing question which most fundamentally affects our general conceptions as to the history and government of the world? And when this question is pressed singly,--how can we account for the appearance of life in the world?--science has no answer to present. Life still remains a mystery in scientific times, as it had been in past ages. Much has been written as to the origin of species; nothing to any purpose has yet been said as to the origin of life itself. The secrets of the universe in this respect have eluded discovery, and a constrained silence is the consequence.