investigating and of expounding in lectures or lay sermons, the changes which itself and its several components have undergone. So far we advance with willing steps like dutiful disciples along the path of knowledge indicated by our distinguished biological teacher, who here, however, pulls us up short by suddenly intimating that he sees no break in the series of transubstantiations whereby precisely such oxygen, hydrogen, nitrogen, and carbon as he is lecturing upon, have become metamorphosed into him, the lecturer, and us, the lectured audience, and cannot 'understand why the language which is applicable to any one term of the series should not be used in regard to any of the others.' Oxygen and hydrogen, he reminds us, are gases, whose particles, at and also much below 32 deg. Fahrenheit, tend to rush away from each other with great force; and this tendency we call a property of each gas. Let oxygen and hydrogen be mixed in certain proportions, and an electric spark passed through them, and they will disappear, and a quantity of water equal in weight to the sum of their weights will appear in their place. But amongst the properties of the water will be some, the direct opposites of those of its components; watery particles, for example, at any temperature not higher than 32 deg. Fahrenheit, tending not to rush asunder, but to cohere into definite geometrical shapes or to build up frosty imitations of vegetable foliage. And let the water be brought into conjunction with ammonia and carbonic acid, and the three will, under certain conditions, give rise to protoplasm, which again, if subjected to a certain succession of processes, will rise by successive stages from protoplasm that gives no other signs of life than those of feeding and reproducing its kind, to protoplasm endowed with the power of spontaneous motion, and finally to protoplasm that thinks and reasons, speculates and philosophises. Now why should any of the various phenomena of life exhibited by these varieties of protoplasm be supposed to be of a different class from the appearances of activity exhibited by any of the varieties of lifeless matter? What reason is there why, for instance, thought should not be termed a property of thinking protoplasm, just as congelation is a property of water, and centrifugience of gas? Professor Huxley protests that he is aware of no reason. We call, he says, the several strange phenomena which are peculiar to water, 'the properties of water, and do not hesitate to believe that in some way or other they result from the properties of the component elements of water. We do not assume that something called _aquosity_ entered into and took possession of the oxide of hydrogen as soon as it was formed, and then guided the aqueous particles to their places in the facets of the crystal or among the leaflets of the hoar frost. On the contrary, we live in the hope and faith that, by the