164 SOME RECENT DEVELOPMENTS 



which he defined as " a kind of mucus endowed 

 with spontaneous movement and contractility." His 

 idea of the physiological activity of the cell-body 

 was very early recognised as important, and 

 Schwann himself expressed the conviction that 

 the study of the cell-body or cell-substance was 

 essential to a true knowledge of the processes of life. 

 The term " protoplasm " that has since come into 

 general use for the cell-substance was first applied 

 to the cell-contents of plants, and was adopted by 

 Max Schultze for animals as well, when in 1861 

 he maintained the fundamental identity of the living 

 matter of animals and plants, however high or how- 

 ever low in grade they might be. 



In 1868 Huxley, in his celebrated lecture at 

 Edinburgh on " The Physical Basis of Life," laid 

 great stress on the fundamental unity of the living 

 matter of animals and plants, maintaining that it is 

 right to speak of life as a property of protoplasm ; 

 and that just as the properties of water e.g., con- 

 vertibility under given conditions of temperature 

 and pressure into steam result from the nature and 

 disposition of its component molecules, so do the 

 properties of protoplasm result from the nature and 

 disposition of its molecules. This idea, really 

 originating with Schwann himself, that the riddle, 

 the mystery of life, was to be solved by study of 

 the molecular constitution of living matter or proto^ 

 plasm was a great conception and in all probability 

 a correct one. However for the moment it 

 checked rather than aided the progress of biological 

 science ; it was too big a jump. Our knowledge 



