Huber-DeWitt, Neiiro-tendinous End-organs. 199 



scribed by Ciaccio seems to us rather like a clamp, partially sur- 

 rounding the tendon, while the spiral is neither uniform nor well 

 marked. The nerve plaque seems in each case to surround 

 fasciculi near the superficial surface of the end-organ, and never 

 or seldom those in the interior, while the larger medullated 

 fibers are found mostly in the deeper parts and their secondary 

 and tertiary branches approach the surface, finally ending in the 

 plaques above described on the smaller tendon bundles of the 

 fasciculi nearest the surface of the end-organ. 



In all these neuro-tendinous end-organs, with all their vari- 

 ations in size and complexity, the same characteristics are 

 noted : Medullated fibers, branching and rebranching, becom- 

 ing non-medullated, the non-medullated fibers being beset by 

 larger or smaller granular enlargements of varied form ; these 

 granular masses were interpreted as nuclei by the older writers, 

 but we beheve with Ciaccio that they are accumulations of neu- 

 roplasm. The complexity of the organ depends largely on the 

 number of medullated branches, while the complexity of the 

 nerve plaque depends rather on the length and number of the 

 non-medullated fibers and the number and size of the charac- 

 teristic granular enlargements besetting them. In the amphibia 

 only, have we observed no characteristic granular enlargements 

 on the varicose fibrils constituting the plaque. In amphibia, 

 the ultimate branches of the nerves ending in the neuro-tendi- 

 nous end-organs are not unhke the ultimate branches of the 

 nerves ending in the neuro-muscular end-organs of these verte- 

 brates as described by Smirnow and the writers, which also dif- 

 fer markedly from the nerve terminations in the neuro-muscular 

 end-organs of other vertebrates. 



The nerve endings in the tendons of the eye-muscles, con- 

 cerning which Ciaccio speaks especially, saying that in man 

 they are found either in the neuro-tendinous end-organs of 

 Golgi, or free on the primary tendon bundles, while in other 

 mammalia, they are only ' in the neuro-tendinous end-organs, 

 have been fully described for the cat by one of us in another 

 communication. 



