216 MODE OF TERMINATION OF MOTOR NERVES, BY W. KUHNE. 



second method must at the same time appear still more im- 

 portant, because it indicates a more intimate connection be- 

 tween nerve and contractile substance than between this and 

 the sarcolemma. 



As regards the methods of investigation, it may here be 

 added, that the greatest possible delicacy in manipulation is 

 required, for the subject is one of the most difficult in the 

 whole range of microscopic art, and is one also on which his- 

 tologists are not, as yet, by any means unanimous, as the short 

 historical sketch at the end of this article sufficiently shows. 

 It is not sufficient to take the muscular fibre from still living 

 and contractile muscles, but care must also be taken that, 

 whilst still under the scrutiny of the observer, they retain 

 their contractility, the covering glass being prevented by 

 supports from exercising any pressure upon them. Fibres 

 affected with rigor mortis are totally unserviceable, and also 

 those which have had their axes rotated, or which have been 

 in any way damaged. Maceration in acids that are at all concen- 

 trated leaves no vestige of the intra-muscular nerves beyond a 

 few interrupted and broken striae. Extremely dilute acids, as 

 acetic acid of O5 per cent., or hydrochloric acid of O'l per cent., 

 do not, indeed, render the image any clearer, but they do not 

 destroy it; the terminal bulbs, however, soften under their 

 influence in quite a peculiar manner, breaking up into a brush- 

 like set of fibres ; a change that stands in strong contrast to the 

 well-known shrinking of the muscle nuclei and of the sheath of 

 Schwann, and most distinctly proves the difference of the cor- 

 puscles of the axis cylinder from those structures. 



The mode of termination of the nerves in Fishes has been 

 hitherto but little investigated; by the application of some of the 

 methods already adopted for the muscles of Amphibia, however, 

 evidence has been obtained that here also the nerves penetrate the 

 sarcolemma, and, at the point of entrance, lose their medullary 

 sheath. The few extended investigations which have been 

 instituted upon the mode of termination of the nerves in the 

 Torpedo ocellata will be mentioned in the following paragraph. 



B. Reptiles, Birds, Mammals. In these animals also the 

 mode of isolating the fibres by means of Budge's solution per- 



