When writing his "Different Forms of Flowers," he said, "I am all on fire at the work;" and of "Insectivorous Plants," "I have been working like a madman at Drosera. Here is a fact for you which is certain as you stand where you are, though you won't believe it, that a bit of hair, 1/78000 of one grain in weight, placed on gland, will cause _one_ of the gland-bearing hairs of Drosera to curve inwards, and will alter the condition of the content of every cell in the foot-stalk of the gland." But he was growing tired with his constant and multifarious labors. He wrote to Hooker: "You ask about my book, and all that I can say is that I am ready to commit suicide; I thought it was decently written, but find so much wants rewriting that it will not be ready to go to printers for two months, and will then make a confoundedly big book. Murray will say that it is no use publishing in the middle of summer, so I do not know what will be the upshot; but I begin to think that every one who publishes a book is a fool." In 1871 the "Descent of Man" was published. He worked on this book three years, and he wrote to his friend, Sir J. D. Hooker, that it has "half killed" him. For the first edition Darwin received over seven thousand dollars. It had an immense circulation in England and America, and created a furor in Germany. Darwin believed "that man is descended from a hairy quadruped, furnished with a tail and pointed ears, probably arboreal in its habits, and an inhabitant of the Old World. This creature, if its whole structure had been examined by a naturalist, would have been classed among the quadrumana, as surely as would the common and still more ancient progenitor of the Old and New World monkeys. "The quadrumana and all the higher mammals are probably derived from an ancient marsupial animal, and this, through a long line of diversified forms, either from some reptile-like or some amphibian-like creature, and this again from some fishlike animal. In the dim obscurity of the past, we can see that the early progenitor of all the vertebrata must have been an aquatic animal, provided with branchiæ, with the two sexes united in the same individual, and with the most important organs of the body (such as the brain and heart) imperfectly developed. This animal seems to have been more like the larvæ of our existing marine Ascidians than any known form." Most naturalists believe, with Darwin, that man has developed from some lower form, but many urge that at some stage of development he received the gift of speech, and mental and moral powers, from an omnipotent Creator. Darwin received much abuse and much ridicule for his views. Mr. James D. Hague tells in "Harper's Magazine" of a visit paid to the great scientist, when a picture in the "Hornet" was shown; the body of a gorilla, with the head of Darwin. The latter laughed and said, "The head is cleverly done, but the gorilla is bad; too much chest; it couldn't be like that."