Cover and illustrated color plates from the 3rd edition of The microscopy of drinking water by George Chandler Whipple. Per the author, the book is designed to serve as a guide for the water analyst and water-works engineer, describing the methods of microscopical examination and assisting in the identification of common microscopic organisms found in drinking water. Notably, the illustrations are drawn primarily from contemporary biological research conducted at the Boston Water Works and reports from the Massachusetts State Board of Health.