reproduced and multiplied by the introduction of fragments of crystalline matter into a supersaturated solution. The resemblance between an osmotic growth and a living organism is much closer than that between a living being and a crystal, there being not only an analogy of form, but also of structure and of function. In order to find the physical parallel to life, we must turn to osmosis and osmotic growth rather than to crystals and crystallization. The first and most striking analogy between living beings and osmotic growths is that of form. The morphogenic power of osmosis gives rise to an infinite variety of forms. An osmotic growth, even at the first sight, suggests the idea of a living thing. One need only glance at the photographs of osmotic productions to recognize the forms of madrepore, fungus, alga, and shell. It is wonderful that a force capable {150} of such marvellous results should have hitherto been almost entirely neglected. A second analogy between vital and osmotic growths is to be found in their structure, both being formed by groups of cells or vesicles separated by osmotic membranes. An osmotic stem, formed by a row of cellular cavities separated by osmotic membranes, has a great structural resemblance to the knotted stems of bamboos, reeds, and the like. The foliaceous expansions of osmotic growths are formed by colonies of cells or vesicles disposed in regular lines, which may present various patterns of innervation, parallel, palmate, or pennate. Many of the lamellar osmotic growths are striped in parallel lines alternately opaque and transparent. The terminal organs have also their enveloping membranes, their pulp and nucleus, just like vegetable forms. The analogies of function are no less remarkable than those of form and structure. Nutrition is perhaps the most elementary and essential vital phenomenon, since without nutrition life cannot exist. Nutrition consists in the absorption of alimentary substances from the surrounding medium, the chemical transformation of such substances, their fixation by intussusception in every part of the organism, and the ejection of the products of combustion into the surrounding medium. Osmotic growths absorb material from the medium in which they grow, submit it to chemical metamorphosis, and eject the waste products of the reaction into the surrounding medium. An osmotic growth moreover exercises choice in the selection of the substances which are offered for its consumption, absorbing some greedily and entirely rejecting others. Thus osmotic growths present all the phenomena of nutrition, the fundamental characteristic of life.