60 Q. Loew; Nature of Living Protoplasm. 



Besides proteids a certain amount of water and mineral salts is also 

 required for the constitution of living matter. Other compounds found in 

 protoplasm arc cither tli.TiiK.-vns (fat and sugar) required for the support 

 of respiration, or are of biological service as tannin or resin, or are mere 

 by-products of metabolism. 



Although it has long ago been recognised that the energy for carrying 

 on vital functions is gained by combustion, it has until recently remained 

 a mystery, how this combustion is caused, and how it is made possible 

 that the heat of respiration is to a certain extent so easily transformed 

 into that chemical energy so wonderfully exhibited in the cells. The key to 

 solve this riddle must be sought in the domain of mtxlern chemistry, and 



