PROTOPLASM 



5 



Its physiology may be studied by placing a few torulse in 

 a solution, containing glucose, C 6 H 12 6 , and urea, CON 2 H 4 , 

 with traces of phosphate of soda, Na 2 HP0 4 , and sulphate of 

 potash, K 2 SO 4 . 



If the vessel is kept all night in a warm place the clear 

 solution will in the morning be seen to be turbid. An 

 examination of a drop of the fluid shows that the turbidity 





FIG. 1. (a) Foam structure of a mixture of olive oil and cane sugar ; (b) Reticu- 

 lated structure of Protoplasm ; (c) Reticulated structure of Protoplasm in the 

 cell of an earth-worm (after BUTSCHLI). 



is due to the presence of myriads of torulse. In a few hours 

 the few torulse placed in the fluid have increased many 

 hundredfold. The whole mass of yeast has grown in amount 

 by the growth and multiplication of the individual units. 



This power of growth and reproduction under suitable 

 conditions is the essential characteristic of living matter. 



What are the conditions necessary for the manifestation of 

 these phenomena of life ? 



