PROTOPLASM 7 



substances which we designate Protoplasm, is that they 

 lose their characteristics with life, that is to say they are no 

 longer protoplasm when life is gone. The properties how- 

 ever which living matter possesses alone of all things, are 

 derived from characteristics of protoplasm both in the living 

 state and from its material basis when life is gone. These 

 properties as usually given are (i) the chemical composition; 

 (2) the power of waste and repair; (3) the power of growth by 

 intus-susception; (4) the power of fertilization and repro- 

 duction, and (5) the power of adaptation. 



i. THE CHEMICAL COMPOSITION 



Chemical composition naturally, is one of the properties 

 of protoplasm which can be obtained only after life is gone, 

 analytical processes invariably killing it. Nevertheless 

 there is no loss of weight after death so presumably the same 

 chemical elements are present. Analyzed in bulk, material 

 that has been living is known to contain Carbon, Hydrogen, 

 Nitrogen, Oxygen, Sulphur, Phosphorus, Fluorine, Chlorine, 

 Silica and metals Na (sodium), K (potassium), Calcium, 

 Mg (magnesium), Fe (iron), etc. The chemical composition 

 is not easy to determine because protoplasm is not a 

 homogeneous substance but a mixture of different substances ; 

 the elements given above are combined in a great variety of 

 ways of which more or less definite compounds called al- 

 buminous compounds, or proteids, albuminoids, and nucleo- 

 proteids (all of which are grouped together under the general 

 term proteins) are universally present. Hoppe-Seyler in 

 1871 analyzing pus cells free from the surrounding fluids, 

 found the following percentages of substances: 



Nuclein 34 . 257 per cent. 



Insoluble substances 20. 566 per cent. 



Lecithin and fat 14 . 383 per cent. 



Cholesterin 7 . 40 per cent. 



Cerebrin 5 . 199 per cent. 



Undetermined albuminoids 13 . 762 per cent. 



Extractives 4-433 per cent. 



