252 PHYSIOLOGY OF MUSCLES AND NKKVI-. 



above all, to the influence of the active nerve. 

 The latter niav perhaps, as \ve have explained in the 

 foregoing paragraphs, be referred back to electric irri- 

 tation. It is thus apparent that muscle and ner\e 

 beha\e essentially in the same way towards irritants. 

 F>ut, remembering that nerves run for part of their 

 course within the muscle, between its fibres, and even 

 penetrate within the very niuscle-tibres, the thought 

 now suggests itself, that perhaps the muscle is in no 

 wav electrically, chemically, thermically, or mechani- 

 cally irritable ; perhaps, when these irritants are allowed 

 to act on the mu-ele. it is only t he hit ra-musciilar nep, 

 which are irritated, and which then in turn act on the 

 muscle-fibres. In other words, we have to determine 

 whether the muscle is only irritable mediately through 

 the nerves, or whether it is also immediately irritable, 

 independently of the nerves, by any irritants. 



The question is not a new one. Albert von Haller, 

 pr.et and physiologist (170S-77), asked it, and even he 

 was not the first, to do so. Haller declared himself in 

 favour of the second of the two above-mentioned possi- 

 bilities. He called this capacity of the muscles to re- 

 ceive independent irritation (Irritabilitat ). and the name 

 has been retained. Haller met with much Opposition 

 from his contemporaries : and a dispute arese which has 

 lasted to the present time. In llaller's days, .f course, 

 onlv the larger nerve-branchings \\ere known. The 

 further the nerves can be traced by means of the micro- 

 M-ope, t he harder does it evidently become to determine 



I he qlle-t i.i]| Ullder di-cllSMoli. 



(i. [n the year 1856, the French physiologisl Claude 

 I'ernard made experiments with a poison brought from 

 (iuiana, which the Indians of that region use to poi.-mi 



