PROTOPLASM 7 



The most essential characteristic of this group of similar 

 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 however w r hich 

 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 intussusception; 

 (4) the power of fertilization and reproduction, and (5) the 

 power of adaptation. 



i. THE CHEMICAL COMPOSITION 



Chemical composition, naturally, is one of the properties 

 of protoplasm w T hich 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 chem- 

 ical elements are present. Analyzed in bulk, material that 

 has been living is known to contain Carbon, Hydrogen, Nitro- 

 gen, Oxygen, Sulphur, Phosphorus, Fluorine, Chlorine, Silica 

 and metals Na (sodium), K (potassium), Ca (calcium), Mg 

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

 not easy to determine because protoplasm is not a homogene- 

 ous 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 albuminous 

 compounds, or proteins, albuminoids, and nucleo-proteins 

 (all of which are grouped together under the general term pro- 

 teins) 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. 



