The question of life on Mars, which in many respects suggests conditions resembling those prevailing on our own globe, has long occupied the attention of men of science, among whom strong advocates of a Martian flora and fauna have not been wanting. If we may accept one of the most recent summaries[1] of the pros and cons of this question, the conditions are not hopeful. Although an atmosphere exists, it appears to be extremely thin; water vapour seems to be present in only very limited quantity; the temperature is very low, and, except in the warmer portions of the planet during the summer season, would be insufficient to support life. The evidence suggests a frigid climate, with dust-storms whirling over vast deserts and salt seas frozen solid, while near the Poles land and sea alike are buried under snow. Summer produces a slight thawing, but even then the cold, salt-saturated soil would appear to be very unfavourable for plant growth. Arrhenius suggests that the presence of a low vegetation such as snow Algæ near the Poles in summer is as much as could be hoped for under the conditions prevailing on Mars. Of the planets whose distance from the Sun is small enough to allow heat and light to reach them in quantity sufficient to permit of vegetation such as we know it, there remains Venus, and here at last we meet with conditions suitable for life. Venus possesses an atmosphere densely charged with water vapour, and maintaining a high temperature all the year round. The conditions prevailing there recall, in fact, those believed to have existed on the Earth during the Carboniferous Period, when our great deposits of coal, composed of the remains of tropical plants, were laid down in marshes and steaming lagoons; but on Venus the conditions are still more extreme--the temperature higher, and the moisture much greater, than those of Carboniferous times. If it is allowable to assume that the prevalence of physical and chemical conditions similar to those which in bygone ages supported an abundant vegetation on our globe, would produce plant life on another world, then we may imagine a luxuriant vegetation on Venus. Whether such an assumption is reasonable is a very interesting and highly speculative question, which the present writer is not competent to discuss. But if one is inclined to indulge in speculation, it may fairly be asked, Why should one limit the possibilities of life to the strict range of conditions under which it is manifested on our Earth? May not the inhabitants of the Sun, ensconced ninety million miles away in a comfortable temperature of 6,500° Centigrade, have long since proved to their own complete satisfaction the impossibility of the existence of life under the appalling conditions of climate prevailing on the Earth? Who can say? There are more things in heaven and earth than are dreamed of in our philosophy. A quotation from one of the foremost of modern men