1. Protoplasm is an emulsion colloid normally in the sol state. 2. The density of protoplasm varies from the very liquid state of young Fucus oögonia and embryos and of streaming protoplasm in myxomycetes and pollen tubes, to the quite viscous condition found in mature and resting eggs of marine organisms. 3. There is a rapid increase in viscosity of the Fucus egg during the last stages of its ripening, which is, on fertilization, followed by a return to the liquid consistency characteristic of active, growing proptolasm. 4. The plasma membrane is a definite morphological structure, constantly and repeatedly capable of repair through the conversion of the fluid protoplasm into a hyaline layer of greater molar concentration. This film of gel is exceedingly elastic, pliable and glutinous. 5. The surface layer, like the interior cytoplasm, seems to be capable of alteration with changes in environment. 6. The capacity for membrane-formation is one of the last essential properties of the living substance to be lost. It is lost only at death. 7. The kind of membrane formed is apparently identical with the parent membrane (except in the case of escaped protoplasm from cells which possess a cellulose wall). 8. The formation of a membrane is probably a purely physical process, but is dependent upon the physiological condition of the protoplasm. It is not dependent upon the surrounding medium. 9. The amount of physical disturbance that protoplasm can be subjected to before showing signs of injury varies from that of the immature Fucus ovum, where it is exceedingly great, to that of the ripe egg where it is very slight, often no more than a touch sufficing to cause disorganization. 10. Gelation of the plasma always takes place in time and is hurried by dissection. It is accompanied by degeneration. 11. Normal protoplasm is at all times non-miscible in water. Miscibility of the plasma is an unfailing criterion of degeneration. 12. Dissolution of the Fucus ovum is the result of the disorganized cytoplasmic matrix going into solution with the surrounding water. This mixing may take place with the rapidity of an explosion, or slowly, and then either continuously or spasmodically. 13. The disintegration of the egg plasm is frequently localized, in that certain regions of the contents continue dissemination of the granules from the beginning, while others join in later, and still others never take part. This indicates a gross structure of the egg plasm, i. e., the protoplasm is composed of many centers of activity in which different chemical reactions take place separated by protective partitions. 14. That any definite and permanent arrangement of the colloidal particles exists seems unlikely. Whatever structure, gross or ultimate, protoplasm may possess is secondary to chemical activity upon which the life of the organism depends.