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Prof. J. C. Bose. On Electromotive Wave [May 21, 



increased response due bo the action of Na 2 C0 3 on Pt. Another record 

 shows an exactly similar effect on tin. The record of effect was taken 

 2 minutes after the application. Other records taken immediately 

 after, show that the enhanced responsiveness takes place gradually 

 with time. (See also fig. 7, and compare the general similarity between 

 the enhancement of response produced by preliminary vibration and 

 by the action of Na 2 C03.) 



Depressants. — Other reagents, like KBr (10 per cent.), produce a 

 depression in the response. There are again others which abolish the 

 response almost completely, for example, 3 per cent. KHO solution 

 (fig. 12, C). One of the most effective reagents which abolishes the 

 response is oxalic acid. The depressing effect of this reagent is so 

 great that a strength of 1 part in 10,000 is often sufficient to produce 

 an abolition of response.* 



Opposite Effects of Varying Strengths of Solution. — The most curious 

 effect is that exhibited by some reagents when the strength of solution 

 is varied. This is clearly seen in the following record (fig. 12), in which 



(a) (b) (O 



Fig. 12. — Records showing the opposite effects of weak and strong solutions, 

 (a) Normal response ; (b) increased response due to addition of 0*3 per cent. 

 KHO ; (c) abolition of response by 3 per cent. KHO. The trace (e) should 

 have been engraved merely as a thick trace. 



(a) gives the normal response in water. KHO solution was now added 

 so as to make the strength 3 parts in a thousand and (b) shows the 



* The various phenomena connected with the response in inorganic substances — 

 the negative variation — the relation between stimulus and response — the increased 

 response after continuous stimulation — the abnormal response converted into 

 normal after long-continued stimulation — the diphasic variation — the increase of 

 response by stimulants, decrease by depressors, and abolition by " poisons," so- 

 called — all these are curiously like the various response phenomena in living 

 tissues. A complete account of the mutual relation between the two classes of 

 phenomena will be found in a work to be shortly published, " On the Response in 

 the Living and Non-living " (Messrs. Longmans). 



