I. Physiological reflections on the natural history of animals and vegetables. Observations and experiments upon the animalcula of infusions. Two epistolary dissertations on infusion animacula addressed to the author, by M. Bonnet of Geneva. Observations and experiments on the seminal vermiculi of man and other animals, with an examination of the celebrated theory of organic molecules.--II. Observations and experiments on the seminal vermiculi [cont'd] Observations and experiments on some singular animals which may be killed and revised. Observations and experiments on the origin of the plantulae of mould. Results of experiments on the reproduction of the head of the garden snail. Experiments on the reproduction of the head of the terrestrial snail, by C. Bonnet. Memoirs on the reproduction of the members of the water newt, by C. Bonnet