The type of subject matter included in this book has been changed from that presented in the first (ED623220) and second (ED623221) books. While the first two books dealt with the elementary facts of biology, this third book is devoted to the facts of chemistry and bacteriology in their simple form. The purpose of this book, moreover, is not merely to arouse the interest of children in the facts of science, but also to arouse a feeling of appreciation for the achievements of science and of scientific men. These facts are presented for the purpose of creating a feeling of appreciation of the relation of science to life, and to introduce the reader to explore further into the applications of science and the accomplishments of scientific men. It is believed that there may be created the beginning of a scientific attitude of mind that will affect not only the child's personal living, but their relation to the community both at the present and in the future. Added to each chapter a list of suggested questions to aid the teacher in the effective use of the texts.