STRUCTURE OF PROTOPLASM. 323 



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 disor- 

 ganized cytoplasmic matrix going into solution with the sur- 

 rounding water. This mixing may take place with the rapidity 

 of an explosion, or slowly, and then either continuously or spas- 

 modically. 



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 chemi- 

 cal activity upon which the life of the organism depends. 



The writer wishes to thank Professor Duncan S. Johnson for 

 suggesting this study and for assistance during its progress. 



