THE BASIS OE LIFE 23 



ferment, by giving him the typhoid germ in such an attenuated 

 form that it cannot do him any harm. 



The chemistry of protoplasm is a science which is growing 

 rapidly, or, to speak less arrogantly and more correctly, our 

 knowledge of the ways of protoplasm, the Chemist, has greatly 

 increased during the last few years. We can but watch proto- 

 plasm at work. Our experiments, so called, are but windows 

 which we open in the walls of his laboratory. We cannot take 

 the work out of his hands. The methods of mineral chemistry 

 are useless in this search for knowledge. And, naturally, the 

 longer we watch, the more details do we discover in what seemed 

 at first a generalized procedure. We recognize that several 

 manipulations are required in the carrying out of a reaction 

 which hitherto we believed to take place in a single stage. This 

 is not the place in which to give an account of a subject re- 

 garded as belonging, owing to its applications, to the province 

 of pathology. But Nature is one, however many be the com- 

 panies into which we divide the explorers of her secrets. We 

 have attempted the merest outline of the observations made 

 up to the present, and have submitted the results for the sake 

 of the light which they throw upon the way in which ferments 

 are prepared as they are wanted to meet the needs of normal 

 everyday digestion and metabolism, rather than for the purpose 

 of showing the methods by which protoplasm combats disease. 



Amongst the chemical phenomena of life is respiration. 

 Respiration in this very general sense means oxidation. The 

 force which is exhibited in living is obtained from the union 

 of organic materials with oxygen under the direction of 

 protoplasm. This is true of plants as well as of animals. 

 It is true even of the subdivision of bacteria, termed 

 anaerobic, because they cannot live in air. They secrete 

 ferments which enable them to decompose compounds which 

 contain oxygen, in order that they may use the oxygen for 

 respiration. It might have been supposed that green plants 

 which are receiving radiant energy from the sun would convert 

 this energy into the forces which enable protoplasm to display 

 the phenomena of life. But this is not so. The energy which 

 green plants obtain from the sun is used in constructive 

 metabolism, and not in maintaining life. Life-force, if 

 we may use the expression, is derived from the oxidation 



