MODE OF TERMINATION OF MOTOR NERVES IN REPTILES. 217 



mits the intimate union of the nerves with the muscular fibres 

 to be proved ; for, if the vascular network which contains the 

 acid mixture have been removed with a brush, a short and 

 frequently divided nerve stump often remains obstinately ad- 

 herent to the fibre. An investigation by Rouget first led to 

 exact conclusions in regard to the mode of termination of the 

 nerves ; since it demonstrated the existence of the Doyerian 

 eminence, in the first instance in lizards, and subsequently in 

 warm-blooded animals. Rouget corroborated the statement 

 he had already made, of the passage of the nerve through the 

 sarcolemma, of the fusion of this with the sheath of Schwann, 

 and added the important observation from his investigation 

 of fresh muscle, such as can easily be obtained from Reptiles, 

 that just beneath the point of entrance of the nerve, a mass 

 of nuclei and granular substance, constituting a Doyerian 

 eminence, may be found exactly similar to that found in Ar- 

 thropoda. And thus, although in the muscles of these animals 

 there exists no such abundance of nucleated and protoplasmic 

 formative material as in Arthropoda, yet this material is ac- 

 cumulated in greatest quantity immediately beneath the ends 

 of the nerves. According to Rouget, the grumous mass, with the 

 nuclei imbedded in it, constitutes the proper termination of the 

 nerves, with which the axis cylinder becomes continuous, and 

 thus modified, rests with a circular or elliptical flat basis on 

 the contractile substance, the cylindrical mass of which it 

 embraces for a certain distance, but never entirely surrounds. 

 The rows of nuclei and of granular material that in Arthropoda 

 extend for some distance along the muscle, are entirely absent 

 in lizards and the warm-blooded vertebrates. The observation 

 of Rouget soon received confirmation, and Krause appears to 

 have been the first who correctly described and represented 

 the nuclei of the nerve eminence, stating them to appear in the 

 fresh muscle as small delicately contoured vesicles, with rela- 

 tively large nucleoli ; whilst, after the death of the muscle, and 

 the addition of even very dilute acids, they become wrinkled 

 and filled with granules. Rouget had only seen, and at a later 

 period depicted them, when thus altered. The nuclei which are 

 seen at the extremity of the nerve are, moreover, not all alike ; 

 one portion belonging to the eminence, and another to the 



