An earnest discussion is going on in the Paris Academy of Sciences in relation to the question whether plants ever grow except from seed, and whether animals are ever created except by the process of being born from parents or hatched from eggs. Mr. Pouchet, a professor at Rouen, and a correspondent of the Academy, contends that he has observed the generation of microscopic plants and animals, under circumstances which precluded the possibility of their coming from either seed, eggs or parents. Bat the correctness of his conclusion] is denied on the ground that eggs or seed may have been floating in the atmosphere, and may thus have entered his solutions in which the organisms which he saw make their appearance. We find in the Presse Scientifique des Deux Mondes an account of an experiment tried by M. Pasteur to determine whether these germs come from the air. He partly filled number of small, hollow glass globes with putrefiable liquor, such as albuminous water, yeast, sugar-water, to which was ad.led a little white of egg, milk, urine, &c, and then melting the necks of the globes with a blow-pipe, ho drew them out into long slender tubes, which he sealed hermetically at the end. He then boiled the contents of the globes to destroy the life of any germs which they might contain, after which he opened them under different circumstances more or less favorable for collecting the dnst from the atmosphere. Some of the slender necks of the globes were straight so that the dust from the atmosphere might fall into them freely, while others were bent in numerous curves to obstruct the entrance of the dust. Some of the globes were opened by breaking off the ends of the necks, a portion of them in the deep cellars of the academy, and a portion in the open court where there was a free circulation r-f air. In those which were not broken there was no growth of mold or other plant, and no appearance of animal life, while in those broken in the open air the organisms were more numerous than those opened in the cellar. From these experiments M. Pastenr concludes that the living plants and animals found in putrefiable liquors come from eggs or germs floating in the air, and are never the product of spontaneous generation. M. Pouchet, and the other advocates of the doctrine of spontaneous generation, reply that the existence of organic dust in the atmosphere was known a long time ago, and that, consequently, nothing new has been learned from the experiments of M. Pasteur. But they add, that while living beings of inconceivable littleness have been found in the air, there have never been discovered any eggs or any germs, and until such are shown, they shall deny their existence, arid shall continue to believe that both plants and animals are pro- duced, under the requisite conditions, without any an-cesters. The weight of opinion in the academy is against the idea of spontiineons generation.