BY Sir RAY LANKESTER K.C.B., F.R.S. WITH NUMEROUS ILLUSTRATIONS NEW YORK THE MACMILLAN COMPANY 1920...

THE present volume is, like its predecessors, "Science from an Easy Chair" (Series I and Series II) and "Diversions of a Naturalist"—mainly a revision and reprint—with considerable additions—of articles published in daily or weekly journals. The first chapter appeared originally in "The Field." The Chapters VI, XX, XXI, and XXII were published in the "Illustrated London News," under the title "About a Number of Things." The rest are some of the articles which, as "Science from an Easy Chair," I

THIS plate shows the restoration of the extinct lizard, Dimetrodon gigas (Cope), lately made by Mr. Charles W. Gilmore of the United States National Museum, by whose kind permission it is here reproduced from the Proceedings of the U.S. National Museum, vol. 56, 1919. It is based upon the study of a very fine skeleton and some hundred bones of allied species, collected by Mr. Sternberg from "the Permian formation" exposed in the vicinity of Seymour, Texas, U.S.A. It is selected for illustration

PORTRAITS OF MAMMOTHS BY MEN WHO SAW THEM SOME fifty-five years ago pieces of reindeer's antler were discovered in the cave known as "La Madeleine" in the Dordogne (a department of France some eighty miles east of Bordeaux), upon which were engraved the outlines of various animals such as reindeer and horses. They and the bone spear-heads and needles, and the flint knives found with them, were the first revelation to later man of the existence of the prehistoric cave-men. Among the carvings was

Nevertheless, the outburst of Vesuvius in A.D. 79 and its re-entrance into a state of activity came upon the unfortunate population around it as an absolutely unexpected thing. At least a thousand years—probably several thousand years—had passed since Vesuvius had become "extinct." All tradition of its prehistoric activity had disappeared, though the learned Greek traveller Strabo had pointed out the indications it presented of having been once a seat of consuming fire. From A.D. 63 there were d

The beautiful blue tint of the semi-transparent "white" of a boiled plover's egg is due to a fine-particled cloud dispersed in the clear albumen. London milk used to be "sky-blue" for a similar reason, before the recent legislation against the adulteration of food. The blue eyes of our fair-haired race and of young foxes are not due to any "pigment"—that is to say, a separable self-coloured substance—but to a fine cloud floating in a transparent medium which reflects blue rays of light as blue s

Returning to our collections of butterflies and meadow flowers, we may take the names of some of the species and genera as an example of the system of naming in use by scientific naturalists. The common swallow-tail is assigned to the genus Papilio. Its "specific name" is "Machaon," given to it by Linnæus, hence it is spoken of as Papilio Machaon. It is found in various parts of Europe as well as in England. But in Central Europe (often seen in Switzerland) there is also another species of swall

Thus one sees how difficult it is to have knowledge of the breeding test, even in regard to large animals. It is obvious that the difficulty of obtaining it in regard to the thousands of kinds of minute creatures is much greater. Yet when they say, "This is a distinct species," naturalists do mean that it is not only marked off from other animals or plants most like to it by a certain shape, colour, or other quality or qualities, but that it breeds apart with its own kind and does not naturally

There is nothing surprising or extraordinary in the existence of variation. The conditions of life and growth are never absolutely identical in two individuals, and the wonder is not that species vary, but that they vary so little. The living substance of animals and plants is an extremely complex chemical substance, ever decomposing and ever being renewed. It is the most "labile" as it is by far the most elaborately built-up chemical body which chemists have ever ventured to imagine. It differs

Crayfishes, lobsters and the like have groups of plume-like gills (corresponding in the most ancient forms to the number of the legs and jaw-legs) overhung and hidden by the sides of the great shield or "head" of the animal. The common lobsters and crayfishes retain most of these in full size and activity, but have lost in the course of geologic ages the original complete number. These plume-like gills—each half an inch or so in length—are attached, some to the bases of the legs and some to the

Nevertheless, in conditions brought about by man—that is to say, confinement in cages or paddocks, or at any rate removal from their native climate and home—all the groups of species just cited commonly and frequently produce hybrids inter se , that is, one or more species of the horse group thus inter-breed with one another, so will certain species of cats, certain species of bears, many species of pheasants, also of ducks, of geese, and of grouse. In nearly every case the hybrids so produced a

When these facts are considered we have to admit that in the mating of two species which will not regularly and naturally breed together, there may be a limited action of the spermatic element which may stimulate the egg to development without contributing by fusion in the regular way to the actual substance of the young so produced, or only contributing an amount insufficient to produce a full and normal development of the hybrid young. Such cases not improbably sometimes occur in higher animal

The most curious of the tube-building Rotifers are those which form their tubes of little, equal-sized pellets of solid matter—as it were, "bricks"—which they first form by compacting fine particles in a special pit on the head and then build them up and cement them together in rows to form the tube, adding row after row as the animal itself increases in length (Fig. 37 ( bis ), C). These are known as Melicerta; and, though some kinds use any minute particles to make their bricks, one kind is fr

All this is ancient history, twenty years and more in the past. The experiments of a French observer, mentioned at the beginning of this chapter as foolishly trumpeted in a London paper, were of service as confirming the extensive and careful work of his predecessors. It is only when our old well-bottled discoveries have, however tardily, been brought before the Paris Academy of Sciences and sent back to us by the Paris correspondents of news agencies as "startling novelties" and "amazing discov

In Figs. 40 to 45 a few examples are shown of the Swastika from various places and ages. It was in use in Japan in ancient times, and is still common there and in Korea. In China, where it is called "wan," it was at one time used, when enclosed in a circle, as a character or pictograph to signify the sun. It has been employed in China from time immemorial to mark sacred or specially honoured works of art, buildings, porcelain, pictures, robes, and is sometimes tattooed on the hands, arms, or bre

Our British coal and a good deal of foreign coal is found in certain stratified rocks of the earth's crust known as "the Carboniferous System," about 12,000 ft. thick, consisting chiefly of very dense limestone. The "seams," or stratified beds of coal, occur in sandy rock known as the "Coal Measures," and vary in thickness from a mere film to 40 ft. Above the Carboniferous System are later deposits, some 14,000 ft. in thickness—the Permian, Triassic, Jurassic, Cretaceous, and Tertiary strata. Be

Since 1870 the industry has spread all over the globe—Russia, Galicia, Rumania, Java, Borneo and Burma being prominent sources of the oil supply of the world. The raw petroleum of different localities differs in each case in the amount of solid paraffins and olefines dissolved in the liquid paraffins. Other substances also are dissolved in it in variable amount—such as benzene, acetylene, camphene and naphthalene. The fact that the oil, when reached by a boring, is often found to be under a cons

A blow to the easy-going belief of the Admiralty that they had mastered and made an end of scurvy was struck when scurvy broke out (60 cases among 122 men) in the expedition to the North Pole which sailed in May 1875 in the Alert and the Discovery , under the command of Sir George Nares. The expedition had to return prematurely after seventeen months' absence, and a committee was appointed to inquire into the cause of the outbreak. The stores of food and of lime-juice were shown to have been amp