38 Mr H. F. Baxter on the Effects of Acids and Alkalies 



that is developed, but rather upon the changes which take 

 place during the chemical reactions ; when the two solutions 

 are placed upon the nerve, then the actions become more 

 complex ; in addition to those acting upon the nerve, we 

 have those arising from the combination between the solu- 

 tions. If the solutions are weak, there may not be sufficient 

 disorganisation of the nerve produced to prevent it from 

 being able to conduct either nervous impressions, or much less 

 a current of electricity, through the part where the solution 

 has been applied ; but if concentrated, then disorganisation 

 takes place, and the nerve becomes incapable of conveying 

 its own impressions, and even perhaps the electric current, 

 so far as to excite nervous action ; so that the conducting 

 power of a nerve under these circumstances becomes a point 

 of some consideration. 



Let us consider for a moment the effects produced by 

 using one solution only, as in my first experiments, and 

 then by adding another. If the weak acid solution be 

 placed near the muscle — no contraction ; let the alkaline so- 

 lution be now placed on the distal side of the nerve — if of 

 sufficient strength, it will cause contractions, in consequence 

 of the acid not destroying the conducting power of the nerve 

 to its own impressions ; but when the combination of the acid 

 with the alkali takes place, we may then have contractions 

 produced, in consequence of the current thus developed, 

 which being direct, going from the alkali to the acid, is 

 favourable for causing contractions. If the acid be too strong, 

 the transmission of the nervous impression is prevented, and 

 very likely the influence of the current also. Let the alkali 

 be placed near the muscle, contractions occur ; now, place 

 the acid upon the distal extremity, — no effect ; the current 

 is now in the reverse direction — unfavourable for producing 

 contractions. Let the two solutions be placed on the nerve, 

 simultaneously, as in Experiment 1, the same reasoning will 

 apply, and it is interesting to observe, that when the No. 2 

 solutions were applied, a difference in the nature of the con- 

 tractions were observed, being slightly tetanic in the limb a. 

 In other experiments also, when the acid was near the 

 muscle, the fibrillar or slight tetanic contractions, were more 

 frequently produced than in the other limb. It may be said 



