CHEMICAL ACTIONS: PROTOPLASM 



against their hosts, have hitherto not been of such 

 general biological interest that we need treat of 

 them. 



This chapter had the purpose of showing that 

 numerous chemical influences are exercised upon 

 living protoplasm by the protein substances 

 of other cells, and that such reactions have a 

 markedly specific feature. The life process can 

 be stimulated or retarded by these influences, 

 production of certain substances can be pro- 

 voked or hindered, and death can even be caused 

 by such cell substances. We learned how far 

 the substantial specificity goes in an organism. 

 The structure in protoplasm is certainly not the 

 only characteristic which is decisive for living 

 substance. We have also continually to keep 

 in mind the chemical nature of the substances 

 in protoplasm. 



Modern chemistry is not yet quite sufficiently 

 advanced to clear up this most interesting complex 

 of reactions between highly composed protein- 

 bodies. It is still the question whether the reac- 

 tions between toxins and their anti-bodies are 

 really of ordinary chemical character, or whether 

 they belong to the territory of colloidal reactions. 

 Here is one of the most suggestive problems 

 of modern Biology. There is no doubt that 

 enormous progress will come from further study 

 of Immunochemistry. 



