THE PHYSICAL BASIS OF LIFE 7 



The body of Man in common with that of all animals and 

 plants is composed of living and non-living matter closely 

 associated, though totally distinct. For example, the 

 visible parts of hair and nails, a large part of bone and the 

 liquid part of blood is non-living material. But, the non- 

 living is not confined to gross structures, for the dead among 

 the living is still revealed until the resolving power of the 

 microscope fails us. 



A. PROTOPLASM 



Although there is a continuous stream of matter and 

 energy flowing through the living individual, nevertheless 

 the physical and chemical study of living matter from what- 

 ever source we take it Mold or Elm, Amoeba or Man - 

 reveals a remarkable similarity in its fundamental factors, 

 and it is to a consideration of what the concept PROTOPLASM 

 holds for the biologist that we now turn. 



As the finer structure of animals and plants came within 

 the range of vision through improvements in microscope 

 lenses, it was gradually recognized that the ultimate living \ 

 part appeared to be a granular, slime-like material. Thus 

 Dujardin, in 1835, designated as sarcode the material forming 

 the bodies of microscopic animals. Purkinje, in 1840, 

 named the formative substance of the developing animal 

 protoplasm, and compared it with the granular material of 

 the growing region of certain plants. Six years later, von 

 Mohl similarly named the contents of the finer structural 

 units of plants. Confirmatory observations came from many 

 sources during the following decade and culminated in the 

 classical studies of Max Schultze and de Bary which estab- 

 lished the full physiological significance of protoplasm as the 

 essentially similar, fundamental, living material of both 

 animals and plants. This reduction of all life phenomena 



