Although everybody must regret that Swammerdam had not good means, and that his work was so sadly brought to a close by poverty and trouble, yet it must be remembered that wealth is not a great incentive to distinction in subjects that require great self-denial, and which are not much valued by what is called public opinion. The temptations incident to, and the real duties of wealth, are as great antagonists of successful scientific research, as poverty. And certainly the frivolity and vice of the wealthier classes of Europe, during the earlier part of the eighteenth century, were not likely to inspire any of their members with a desire for natural science. But some very remarkable instances occurred, in which the genius and determination of some great men prevailed over the intolerance and habits of the age, and enabled them to become men of great mark in zoology and other subjects. The first to be noticed is René Antoine Ferchault de Réaumur, who was born at Rochelle, in western France, in 1683. Well born, and having wealthy parents, he was well educated, and destined for the law. He did not follow the propensities of the age, but began to study the arts and manufactures of France with great care, and to spend his spare time in natural history researches. From what is known of his career, it is very evident that he had learned chemistry and mineralogy, and that his education had been a most careful and liberal one. His fortune was considerable, and it not being necessary for him to work for his bread, he determined to follow the bent of his inclinations. When twenty years of age, Réaumur went to Paris, and his first essay was in the form of some geometrical work which was read before the Academy of Sciences. At the early age of twenty-four he was admitted a member of that learned and somewhat emotional body, and was a very constant contributor to its publications for fifty years. At first his desire was to improve the arts and manufactures of his native land, and in 1711 he made experiments upon the manufacture of ropes, and he showed that the strength of a cord is less than the sum of the strength of the threads of which it consists, whence it follows that the less a rope is twisted after a certain point, the stronger it is. In 1715 he began to study the process of colouring artificial pearls, and probably it was during these researches that his attention was attracted towards natural history. He found out the nature of the substance which gives the pearly lustre to fish scales, and then he investigated the growth of scales. Following up his subject, he examined into the method of growth of the shells of molluscs. In one of his journeys in Languedoc, he discovered some substances resembling turquoise in colour, and they were used as gems; but he pushed the matter further, and discovered a very remarkable fact. The extinct animal called mastodon, from the peculiar teat-shaped projections on