INORGANIC RESPONSE 147 



to students of physiological response but also known in 

 medical practice, namely that of the opposite effects pro- 

 duced by the same reagent when given in large or in 

 small doses. Here, too, we have the same phenomena 

 reproduced in an extraordinary manner in inorganic 

 response. The same reagent which becomes a ' poison ' 

 in large quantities may act as a stimulant when applied in 

 small doses. This is seen in record fio*. 94, in which 



o 



(a) gives the normal responses in water ; KHO solution 

 was now added so as to make the strength three parts in 

 1,000, and (b) shows the consequent enhancement of 

 response. A further quantity of KHO was added so 

 as to increase the strength to three parts in 100. This 

 caused a complete abolition (c) of response. 



It will thus be seen that as in the case of animal 

 tissues and of plants, so also in metals, the electrical 

 responses are exalted by the action of stimulants, 

 lowered by depressants, and completely abolished by 

 certain other reagents. The parallelism will thus be 

 found complete in every detail between the phenomena 

 of response in the organic and the inorganic. 



