down; every one whose avocations in life had to do with the rearing or use of living things found himself a party to the experiment on a gigantic scale,' which had been going on ever since the human race withdrew for their own ends plants or animals from the feral and brought them into the domesticated state." Anyone who, having read Mr. Darwin, has visited, for instance, the show of the Royal Agricultural Society, must have been continually reminded of his observations on "Selection by Man." Indeed the work on the Variation of Animals would be an excellent text book for the show! Mr. Darwin chiefly deals with the minute variations which have been patiently developed by the breeder and the fancier, but in some cases, as he shows in one remarkable passage, new breeds have suddenly appeared. Thus in 1791 a ram lamb was born in Massachusetts, having short crooked legs and a long back, like a turnspit dog, and so was raised the Ancon breed, which, it was supposed, would be valuable because the animals were not able to leap the fences; but they have been supplanted by Merinos. Again, in 1828, a Merino lamb, born on the Mauchamp farm in France, was the parent of the Mauchamp Merinos, with peculiarly valuable fleece; and Mr. Darwin adds 66 If these breeds had originated a century or two ago we should have had no record of their birth; and many a naturalist would no doubt have insisted, especially in the case of the Mauchamp race, that they had descended from or been crossed with some unknown aboriginal form.' Round the next work, the Descent of Man and Selection in Relation to Sex (1871), the storms of controversy raged for a time with renewed violence, but only to die away again as they had died before; and in the following year a book on the Expression of the Emotions in Man and Animals must have helped to put the sternest opponent in good humour with a writer who could instruct him in so pleasant a fashion. Insectivorous Plants in 1875, the Effects of Cross and Self Fertilization in the Vegetable Kingdom in 1876, and the Different Forms of Flowers on Plants of the Same Species in 1877, supplied more astonishing evidence than ever of the fertility of resource and the rapidity of production which Mr. Darwin associated with his unsurpassed accuracy and attention to detail. To give any description of these works is impossible; Mr. Wallace says they revolutionized the science of botany. In the next work, the Power of Movement in Plants (1880), sometimes called the "Circumnutation of Plants," it is interesting to find the name of Francis Darwin associated with his father's on the title page, while Mr. George Darwin assisted in illustrating it; and assistance received from the same source, as well as from his sons William and Horace, is mentioned in Mr. Darwin's last volume, the Formation of Vegetable Mould,1 published in 1881, the year before his death. Indeed Mr. Darwin was fortunate in the help he received, not from his own family alone, but from many observers in different parts of the world; nor can we wonder at this, for every small service received a generous acknowledgment; and, as a writer in the Athenæum says, many persons, in conducting their researches, have had, at the bottom of their hearts, the hope to please Mr. Darwin, and to gain his approbation." 66 For the unscientific reader the book on Earth Worms is perhaps one of the most interesting of Mr. Darwin's works. It is full of curious facts. We learn that worms have no sense of hearing, but they seem to be sensitive in some degree to light and heat; they have a feeble sense of smell, and a decided preference for certain kinds of food over others. For example, they are fond of the leaves of the wild cherry and carrots, preferring them to those of cabbages and turnips, and although horse-raddish leaves are a favourite food, they neglect them when they can get those of onions. After reading what Mr. Darwin says about the way in which 1 The full title is the Formation of Vegetable Mould through the Action of Worms, with Observations on their Habits. 66 worms draw various objects into their holes, generally seizing leaves by the thinner end, and even doing the same with paper triangles, it is almost impossible to doubt that they possess some degree of intelligence. Their burrows are not mere excavations, but may rather be compared with tunnels lined with cement, and they appear to take elaborate precautions to protect themselves against the cold. The most surprising part of Mr. Darwin's book, however, is that in which he describes the work of the earth-worms in ploughing the soil and gradually changing much of the surface of the globe. In many parts of England a weight of more than ten tons per acre passes annually through their bodies; and the experiments at Down, which have been already mentioned, show that the mould was thrown up at an average rate of 22 inches in a hundred years. December, 1842, part of a field near Down House was covered with broken chalk, and when a trench was dug in November, 1871, a line of white nodules could be traced seven inches below the surface. Another field, which was converted into pasture in 1841, was called the stony field," and Mr. Darwin wondered whether he should live to see the larger flints covered; but, thirty years after, a horse could gallop over the compact turf from one end to the other and not strike a single stone with his shoes. Farmers can understand now how lime, cinders, and heavy stone, "work downwards"; and why some of their fields, when they are ploughed up, are so full of stones. " In One of the chapters is devoted to the part which worms have played in the burial of ancient buildings ; and this chapter has a local interest, for two of its illustrations are drawn from the neighbourhood of Shrewsbury. Archæologists are probably not aware how much they owe to worms for the preservation of many ancient objects. Coins, gold ornaments, stone implements, &c., if dropped on the surface of the ground, will infallibly be buried by the castings of worms in a few years, and will thus be safely preserved, until the land at some future time is turned up. For instance, |