438 



Dr. W. Kiihne. On the 



Now since we have just employed an electric stimulus which is 

 equally effectual on muscle and nerve, it follows that we had to do 

 with the first case ; that is to say, the muscle showed itself free from 

 nerve at its end. We have reason for specially bringing forward this 

 experimental proof of the absence of any kind of nerves in large tracts 

 of muscle, because it compels those who in spite of all assume the 

 presence of nervous matter in certain microscopic disks and striee of 

 the muscle-fibre as a whole, to deny that this supposed nervous 

 element possesses any power of conducting in both directions or any 

 irritability at all ; for in fact it is not possible to excite the, motor 

 nerve of a muscle-fibre by any stimulus whatever applied to the actual 

 terminations of the nerve within the fibre. The facts besides combine 

 to prove, as need hardly be said, yet another proposition — they prove 

 at the same time that pure muscular excitation does not travel back 

 to the nerves. 



This may be shown still better with the small pectoral muscles of 

 the frog's skin than with the m. gracilis. We need only dissect it in 



Fig. 7. 









f 





1 



n - 













the manner shown in the drawing (fig. 7) and stimulate the spots n 

 and M ; if we stimulate n everything contracts, if M the excited half 

 only. 



The preparation which you now see (corresponding to fig. 2), and 

 which shows the nervation of the very thin muscle with all the nerve- 

 endings stained dark with gold, makes that relation clear, for here again 

 in truth the result of morphological research is in gratifying accordance 

 with results obtained experimentally. The muscle is seen to be for the 

 most part free from nerves ; indeed the entire nervation with all the 

 nerve-endings might be said to be formed of one nerve line only, if we 

 disregard the few digressing fibres which again in part are not motor. 



Under rather higher powers we see the nerve-endings proper (fig. 8), 

 the distinct demonstration of which by means of the gold method has 

 now been achieved, in much the same way as here, in all the classes 

 of vertebrates with the exception of the osseous fishes. In all cases 

 these decisive preparations have proved that the vastly preponderant 

 number of the muscle-fibres is entirely free of nerves, and that the 



