CELLS AND TISSUES. 43 



both take part in the ion effect it must be possible to 

 demonstrate the law of additive ion effects. If, however, 

 the ion effect is connected with but one of the ions, 

 then it is dependent only upon the concentration of the 

 effective ion, and a variation in the opposite ion must, 

 under otherwise unchanged conditions, be indifferent. 

 The role of the electrically neutral molecules springs 

 into prominence in proportion as the degree of electro- 

 lytic dissociation is decreased.'' 



Examples of such ion effects are to be found in the 

 papers of DRESER on the pharmacology of mercury, of 

 LOEB on the absorption of water by muscle and in his 

 much-discussed experiments on artificial parthenogenesis, 

 of HOBER on the sense of taste, of SPIRO with SCHEURLEN 

 and BRUNS, as well as PAUL and KRONIG, on the founda- 

 tions of disinfection, of PAULI on changes in state in the 

 proteins, etc. The laws governing the simultaneous 

 action of several electrolytes can also be deduced from 

 the ionic theory. PAULI and RONA have recently dis- 

 covered an antagonism between the effects of different 

 electrolytes and some non-electrolytes on the changes in 

 state in colloids. 



In the living animal we have to deal with complex 

 mixtures of crystalloids and colloids, between which 

 there exist relations so varied that they are in part still 

 incapable of investigation. Connected with the uninter- 

 rupted vital activity of the cell, the anabolism and cat- 

 abolism of its substance, is the conversion of crystalloids 

 into colloids and colloids into crystalloids, and this at 

 present still entirely unexplained transformation serves 

 at one time to protect a substance from oxidation, as in 

 the conversion of sugar into the colloidal glycogen, while 



