THE LIVING SUBSTANCE 7 



lily, is one of the few authentic records of old seeds still capable 

 of germination.) The average seed contains from 15 to 30 per 

 cent of water. An extraordinary example of minimum water 

 content in protoplasm is that of the so-called sclerotium of slime 

 molds. A slime mold may do one of two things when winter 

 comes or when food is exhausted or unusual dryness prevails. 

 It may form spores (reproductive cells), or it may dry out to a 

 great extent and cease all visible activity. This dried proto- 

 plasm is known as the sclerotium, and it resembles nothing more 

 closely than a bit of thin leather. It is exceedingly stiff and 

 often breaks with the brittleness of glass. This fact gives one 

 quite a different concept of living protoplasm from that com- 

 monly held. In this condition it may last for years, yet when 

 given moisture, warmth, and food, it will start flowing and again 

 become an active living sheet of protoplasm. 



Among the earlier determinations of the chemical constitution 

 of protoplasm is that of Reinke on the plasmodia of myxomycetes. 

 This material was chosen because it is the only pure protoplasm 

 which can be had in relatively large quantities. Animal bodies 

 have much accessory material such as fat and sinew. The 

 analysis of Reinke yielded: 



Per Cent Per Cent 



Proteins 55 Cholesterin 2 



Fats 12 Resins 1 



Carbohydrates 12 Salts 7 



Undetermined 11 



The more recent work of Kiesel shows the composition of the 

 dry (water-free) Plasmodium of the slime mold Reticularia to be: 



Per Cent Per Cent 



Albumin 20.65 Lecithin 4.67 



Plastin (protein) 8 . 42 Cholesterin . 58 



Nucleic acids 3 . 68 Carbohydrates 8 . 06 



Nitrogen-containing extracts 12.00 Glycogen 15.24 



Oils 17.85 Unknown 8.85 



The composition of the human body is 65 per cent water, 15 per 

 cent protein, 14 per cent fat, 5 per cent salt, and 1 per cent uni- 

 dentified matter, representing the following elements (in order 

 of abundance): oxygen, carbon, hydrogen, nitrogen, calcium, 



