rious projects of the search which it is one of the aims of the organization to carry out. President Spottiswoode's address was an elaborate and excellent performance, treating first of the history, influence, and policy, of the Association with which he has long been connected as treasurer, and then taking up the subject of mathematics, which is the specialty he cultivates. His treatment of this subject is highly instructive, and at the present time most opportune. He not only presents very forcibly the general interest and claims of the subject, but he takes up certain curious aspects of it that have recently excited much curiosity and attention, and among these the perplexing topic of the fourth dimension of space. His address in full, together with that of Prof. Newcomb, will appear in the next issue of The Popular Science Monthly Supplement.
We print this month the third and last installment of an introductory essay on the nature and properties of protoplasm, by Dr. Montgomery. The author has made this subject a matter of observation, experiment, and profound reflection, for many years; and his views cannot fail to receive the critical attention of philosophical biologists. Dr. Montgomery is deeply impressed with the immense scientific importance of this comparatively new field of exploration, and we think he does not in the least exaggerate the serious interest of the questions opened by this line of study. Protoplasm is the physical basis of life, and its problems are the initial problems of life. Protoplasm is a living substance endowed with capacities of vital movement, and the question of the origin of life is narrowly and sharply a question of the origin and production of protoplasm. It may never be answered, and many think it would be a dreadful thing if it should be answered. All other mysteries of Nature, they hold, may be properly explored, but to explore and explain this is nothing short of stealing a divine secret. Yet if the mystery can never be cleared up, as they assure us, then surely there is no harm in probing it; while, if it can, the fact itself is proof that it ought to be done, and that no harm will result.
But, whatever may be the final event, Dr. Montgomery has at any rate put the issue in a nice little nutshell. There is a gulf between the organic and the inorganic worlds which we are impressively assured is broader than the Pacific, and can never be fathomed; Dr. Montgomery says that, by the chemical substitution of an atom of hydrogen for an atom of oxygen, it will disappear. He remarks: