CHAPTER V 



PROTOPLASM 



Protoplasm is invariably associated with life, and so far as is now 

 known life can exist in no other substance. When protoplasm ceases to 

 be living, it quickly undergoes destructive chemical changes which reduce 

 it to other and simpler compounds. 



26. Historical Facts. — Protoplasm was first determined to be a 

 particular substance, with characters of its own, in 1835, when it was 

 described as existing in animals, by a Frenchman, Dujardin, who called 

 it sarcode. The protoplasm of plants was first described in 1846 by a 

 German, Von Mohl, who attached to it the name of protoplasm. This 

 name had been used six years before by Purkinje but in a very restricted 

 sense. That sarcode and protoplasm were one and the same substance 

 was most thoroughly demonstrated by Max Schultze in 1861, and to this 

 living substance, common to both plants and animals, is now applied the 

 name given by Von Mohl. 



27. Chemical Character of Protoplasm. — Protoplasm eludes exact 

 chemical analysis. The chemical composition of an animal body may be 

 determined, but this includes the skeleton, stored food, and other mate- 

 rials which are nonliving. To secure a mass of perfectly pure protoplasm 

 is difficult, and the exact analysis impossible. Nevertheless, certain 

 general statements can be safely made. 



1. It is almost entirely composed of 12 elements, including the 

 following : 



Element 



Approximate 

 percentage 



Oxygen 



Carbon 



Hydrogen 



Nitrogen 



Sulphur 



Iron 



Calcium 



Magnesium 



Sodium 



Potassium 



Phosphorus 



Chlorine 



18 



65 



20 



10 



3 



