PHARMACODYNAMICS OF SALTS AND DRUGS 117 



other factors, of the egg. Salts may cause extrusion either by 

 increasing the energy in the egg, or by decreasing the surface tension. 

 Unfortunately the end-points were not determined accurately in 

 many instances, but the figures (Table 10) suffice to show that the 

 stimulation of this particular function was greatest in copper and 

 cadmium, fell to nothing in manganese, was doubtful in magnesium, 

 and then increased as salts having anions of higher ionic potential 

 were used. In other words, if we begin with manganese or magne- 

 sium chlorides and pass to salts having a higher potential energy of 

 either the anion or cation, this function is stimulated, and less of the 

 salt must be used as the energy content increases. 



GENERAL CONCLUSONS. 



The general conclusions of this investigation are: 



1. The action of salts upon the protoplasmic system is due chiefly 

 to the ions of the salt. 



2. The particular result obtained toxic, stimulation, or depres- 

 sion excited by any salt solution is caused, in part at least, by the 

 substitution of the ions in the protoplasmic system, and in large measure 

 in combination with the protoplasmic colloids, by the ions of the 

 salt solution used. 



3. This substitution causes a disturbance of the equilibrium 

 of the protoplasmic system, which, if sufficiently pronounced, leads 

 to destruction. 



4. The power oj different ions to upset the ordinary state of the 

 protoplasmic system depends on the difference between the potential 

 energy content of the ion which is replaced^ and that which is intro- 

 duced. This difference in potential energy content is determined by 

 the difference in the intensity factor of the potential energy of the 

 ions i. e., by differences in the ionic potentials. 



5. It follows from 4 that the ions must arrange themselves in 

 toxic power according to their available potential energy contents 

 (ionic potentials). This was shown to be the case not only for toxic 

 action, but also for stimulating and depressing action. 



6. It was shown that a good numerical relation exists between 

 the available potential energy of any salt and its minimum fatal 

 dose, so that for simple systems the minimum fatal dose can be very 



