Lamarck, poor, neglected, and blind in his old age, died in 1829. Both Cuvier, who ridiculed him, and Goethe, who never heard of him, passed away three years later. The year following his death, when Darwin was an undergraduate at Cambridge, Lyell published his Principles of Geology, a work destined to assist in paving the way for the removal of one difficulty attending the solution of the theory of the origin of species, namely, the vast period of time for the life-history of the globe which that theory demands. As Lyell, however, was then a believer--although, like a few others of his time, of wavering type--in the fixity of species, he had other aims in view than those to which his book contributed. But he wrote with an open mind, not being, as Herbert Spencer says of Hugh Miller, "a theologian studying geology." Following the theories of uniformity of action laid down by Hutton, by Buffon, and by that industrious surveyor, William Smith, who travelled the length and breadth of England, mapping out the sequence of the rocks, and tabulating the fossils special to each stratum, Lyell demonstrated in detail that the formation and features of the earth's crust are explained by the operation of causes still active. He was one among others, each working independently at different branches of research; each, unwittingly, collecting evidence which would help to demolish old ideas, and support new theories. A year after the Principles of Geology appeared, there crept unnoticed into the world a treatise, by one Patrick Matthew, on Naval Timber and Arboriculture, under which unexciting title Darwin's theory was anticipated. Of this, however, as of a still earlier anticipation, more presently. About this period Von Baer, in examining the embryos of animals, showed that creatures so unlike one another in their adult state as fishes, lizards, lions, and men, resemble one another so closely in the earlier stages of their development that no differences can be detected between them. But Von Baer was himself anticipated by Meckel, who wrote as follows in 1811: "There is no good physiologist who has not been struck, incidentally, by the observation that the original form of all organisms is one and the same, and that out of this one form, all, the lowest as well as the highest, are developed in such a manner that the latter pass through the permanent forms of the former as transitory stages" (Osborn's From the Greeks to Darwin, p. 212). In botany Conrad Sprengel, who belongs to the eighteenth century, had shown the work effected by insects in the fertilization of plants. Following his researches, Robert Brown made clear the mode of the development of plants, and Sir William Hooker traced their habits and geographical distribution. Von Mohl discovered that material basis of both plant and animal which he named "protoplasm." In 1844, nine years before Von Mohl told the story of the building-up of life from a seemingly structureless