by the example of the seed of trees; and they added, with some foundation, metaphysical reasonings, by which they proved that great and small being only relations, the transition from small to great, or from great to small, was executed by nature with still more facility than we can conceive. Besides, continue they, have we not very frequent examples of transformation in insects? do we not see small aquatic worms become winged animals, by only throwing off their coats, which were their apparent and external forms? and may not spermatic animals, by a similar transformation, become perfect animals? All therefore, they conclude, concurs to favour this system of generation, and confuting that founded on eggs; and if there are eggs in viviparous females, the same as in the oviparous, these eggs will only be the necessary matter for the growth of the spermatic worm, which enters into the egg by the pedicle that adheres to the ovarium, and where it meets with food ready prepared for it. All the worms which find not this passage through the pedicle into the egg will perish, and that one which alone has traced its way will arrive at its transformation. The difficulty of meeting with the passage in the pedicle of the egg, can only be compensated by the infinite number of spermatic worms. It is a million to one that any particular spermatic worm will meet with the pedicle of the egg, and therefore what at first appears a profusion is highly necessary. When one has entered, no other can introduce itself, because, say they, the first worm entirely shuts up the passage, or there is a valve at the entrance of the pedicle, which is free when the egg is not absolutely full; but when the worm has filled the egg, the valve can no longer open although impelled by another worm. This valve is very well imagined, because, if the first worm should chance to return, it opposes its egress, and obliges it to remain and undergo the transformation. The spermatic worm then becomes the foetus, the substance of the egg its food, the membranes, its covering, and when the nutriment in the egg is nearly exhausted, the foetus adheres to the internal skin of the matrix, and thus derives nourishment from the parent's blood, till by its weight, and augmentation of its strength, it breaks through its imprisonment, and comes perfect into the world. By this system it was not the first woman who inclosed all mankind, but the first man who contained all posterity in his body. The pre-existing germs are no longer embryos without light, inclosed in the eggs, and contained one in another, ad infinitum; but they are small animals, the little homunculæ organized and actually living, included in each other in endless succession, and to which nothing is wanting for them to become perfect animals, and human beings, but expansion, assisted by a transformation similar to that which winged insects undergo.