IDIO OR NERVO-MUSCULAR IRRITABILITY. 137 



by Kulme. Both these authors believe in the con- 

 tractility of the fibre, independently of nerves ; but 

 Schiff thinks the two modes have some essential 

 difference, while Klihne accepts the terms in the sense 

 that the fibre has inherent contractility which may 

 respond to other stimuli than that of the nerves. No- 

 one of late, except Fletcher, attributed the faculty to- 

 some living matter not the actual fibre within the 

 muscle as a whole, till now Beale makes a real and 

 absolute distinction between these two expressions, 

 and denies altogether the idio-muscular actions. 



The arguments that irritability resides in the muscle as a 

 whole, independently of the motor nerve trunks and the blood- 

 vessels, are, it is here taken for granted, unanswerable ; but it 

 is also generally assumed that it must reside in the primitive 

 fibre itself, and it is even asserted that the fibre can be seen to 

 contract on the direct application of stimuli, when destitute of 

 nerves. This point demands special examination, and the chief 

 proofs of it rest on Kiihne's experiments,* so we had better 

 consider these a little in detail. 



The cardinal point is the structure of the sartorius muscle 

 of the frog in respect to the motor nerves. The main trunk of 

 the motor nerve is said to enter about the middle of the muscle, 

 and branch out towards both extremities in ever diminishing 

 size and number of twigs, so that there are five zones of nerve 

 supply, and corresponding irritability. These diminish gradually, 

 and the zones at the extremities possess no nerve fibres at all. 

 Thus two-fifths of the muscle are said to have no nerve fibres, 

 and on this all his results hinge. And, from a variety of ex- 

 periments, he concludes that " the excitability of the muscle 

 stands in the closest connection with its nerve distribution" 



* TTutersuclmngen uber Bewegungen und Yeranderungen der Con- 

 traktilen Substanzen. Von Dr. W. Kuhne. Eeichert and Dubois' 

 " Arcliiv," 1859, heft. 5 and 6. 



