WHENCE THE MUSCLE FORCE ? 135 



Whence, then, these " external forces 1" Here the same 

 philosophical caution is displayed, and no theory entered on till 

 an anatomical basis is discovered. His theory implies that not 

 only the stimulus, but the whole force for muscular action and 

 work is furnished by the motor nerves, and this is founded 

 mainly on the demonstration by his own anatomical prepara- 

 tions of the invariable presence of motor nerve fibres in con- 

 nection with all muscular forms. 



The chief facts concerning the ultimate distribution of the 

 muscular nerves are already given, being included in the general 

 anatomy of nerve distribution. But with respect to the muscles 

 specially, he holds that in addition to the generally accepted 

 plexiform arrangement of the dark-bordered nerve trunks and 

 fibres, and their ramifying distribution to the muscles, numerous 

 far finer fibres proceed from these, and pursue a tortuous course, 

 frequently crossing the muscular bundles. These fine fibres 

 continue to subdivide, and finally terminate in plexuses or 

 loops, never by free ends. Moreover, contrary to anatomists 

 who assert that muscular fibres may receive nerves at one or 

 two points only, and that considerable portion of the ends of 

 muscles are destitute of nervous supply, he asserts " I have 

 been led to conclude that every muscular fibre is crossed by 

 very delicate nerve fibres frequently, and at short intervals, the 

 intervals varying much in different cases, but I believe never 

 being of greater extent than the intervals between the capillary 

 vessels" (" Biopl.," p. 250). He asserts also, contrary to the 

 opinion of Doyere and Kiihne (Strieker, Syd. Soc., i. 207), 

 and others, that the nerve fibres never penetrate the sarco- 

 lemma, but always cross and ramify on the outside of it. 

 Likewise, contrary to the opinion of Kiihne (Strieker, i. 223), 

 that no general scheme of muscle-nerve distribution can be 

 laid down from its extreme variety in different animals, Beale 

 states " On the other hand, my observations lead me to the 

 conclusion that the arrangement is in its essential points the 

 same in all classes of animals. In no case are there nerve 

 ends, but always plexuses, or networks, which are never in 

 structural continuity with the contractile tissue of the muscle" 

 (" Biopl.," p. 260). 



