CHAPTER IT. 



THE CHEMISTRY OF PROTOPLASM. 



Before commencing our study of the physiology of the 

 Invertehrata in detail, we offer a few remarks concerning the 

 chemical nature and supposed composition of protoplasm,* 

 or albumin. As the complex molecule of albumin is the 

 basis of all physiological functions — in fact, "the physical 

 basis of life" — no apology is needed in bringing this chapter 

 before the attention of our readers. 



Many chemists have submitted albumin to ultimate ana- 

 lyses. Among these may be mentioned the following : — 



Besides the above elements, there is always present in proto- 

 plasm a small, but variable, amount of ash, which contains 

 phosphorus and other elements in infinitesimal quantities. 



* From TrpwTos (first), and vKiaiia (formed substance). 



