Written in response to Thomas Huxley's famous essay on the nature of life, Stirling's work explores the complex and controversial concept of protoplasm. Arguing that protoplasm is the essential material basis of all living organisms, this book offers a fascinating glimpse into the cutting-edge science of the mid-19th century. This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work is in the "public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.