308 PROFESSOR MATTEUCCl'S ELECTRO-PHYSIOLOGICAL RESEARCHES. 



flection diminishes and the needle returns to zero, where it remains if the action of 

 the alkali be repeated, or the solution too concentrated. This effect is identical with 

 that already described, which occurs in the muscular elements immersed for a few 

 seconds in acid or alkaline solutions. In the manner of conducting the experiment 

 (fig. 13.) which we have adopted, in order to excite the muscles to contraction, we 

 touch with the alkali such points of the muscles as are in a certain manner out of the 

 circuit, and which certainly do not constitute the electromotor part of the element. 

 In the pile of entire frogs, with which we succeed oftenest in obtaining signs of in- 

 crease of the current for a few seconds, on touching the lumbar plexuses alone with 

 the alkali, these signs of increased intensity never occur if the entire muscular surface 

 be bathed with an alkaline solution. I will add, moreover, that if an acid solution be 

 employed, and care be taken to touch the lumbar plexuses only with a paint-brush, 

 carefully avoiding the muscles of the thighs or legs, the deflection is not diminished, 

 and in spite of the contractions which are excited, although these are less than those 

 which the alkali occasions applied upon the muscles, there is no increased deflection. 

 The surface of the muscle must be touched with the acid to make the needle fall. 

 The same occurs with the alkali, and is, I repeat, in accordance with the experiments 

 already referred to with the muscular elements which have been immersed in the 

 acid or alkaline solutions. 



It is then only with the pile of entire frogs, and only when the lumbar plexuses of 

 these alone are touched with the alkali, that sometimes a slight increase of deflection 

 is perceived, while this does not occur when acids are similarly applied. Taking up 

 our ground upon the strength of all the experiments described above, it is impossible 

 to consider this result as contrary to the absolute answer in the negative given above 

 to the question whether there were development of electricity in muscular con- 

 traction. 



In the course of the present memoir other irrefragable proofs will be adduced in 

 support of the assertion to the contrary. It is impossible for anybody who looks well 

 to the whole of these phenomena, not to perceive the difficulty which occurs in en- 

 deavouring to explain why, in the particular case described above, the alkali should 

 produce an increase of deflection in the proper current of the pile of entire frogs. 

 For myself, I incline to the belief that stronger and more permanent contractions 

 being excited by the alkali than by acids, the contact between one element and the 

 other becomes thereby more intimately established in the greater number of cases, 

 and, by that means, the internal conducting power is increased. In effect, this contact 

 is very imperfectly established in the pile of entire frogs, and very great difference in 

 the intensity of the current is perceptible with the same elements by improving their 

 mutual contact. 



Whatever may be the right interpretation of the slight increase which occurs in 

 the intensity of the proper current, on touching the lumbar plexuses of the frogs, 

 and thus exciting muscular contractions, certainly this fact alone is insufficient to 



