Philosopher Nicolas Malebranche was the first to advance the hypothesis that each embryo could contain even smaller embryos ad infinitum, like a Matryoshka doll. According to Malebranche, "an infinite series of plants and animals were contained within the seed or the egg, but only naturalists with sufficient skill and experience could detect their presence." (Magner 158-9)[1] In fact, Malebranche only alleged this, observing that if microscopes enabled us to see very little animals and plants, maybe even smaller creatures could exist.