Huber-DeWitt, Neuro-tendinoiis End-organs. 185 



results, however, are more in accord with those of Ciaccio, 

 who, investigating with the gold chloride method the nerve 

 endings in the tendons of the wing muscles of the sparrow, the 

 sparling and the swallow, found the nerve plaques always in 

 the neuro-tendinous end-organs of Golgi, surrounded by a con- 

 nective tissue sheath and an endothelial investment. He finds 

 that usually only one nerve fiber innervates the organ ; this may 

 divide, either before or after entering, into two primary branches 

 each passing toward an opposite extremity of the organ. They 

 divide and subdivide into many non-medullated nerves, which 

 form the plaques, appearing as a multitude of small pieces of 

 axis cylinders, differently formed and grouped in masses 

 ("groupes en amas "). His cross sections show that the nerves 

 pass between the small bundles of fibrillar connective tissue of 

 which the tendon fasciculi are composed, embracing one or sev- 

 eral of them before ending. 



Ciaccio's results regarding the general structure of the or- 

 gan in birds have been in most particulars corroborated by our 

 observations with the mtra-vitam methylen-blue method, on the 

 tendons of the wing muscles of doves. Although in most 

 cases the ending has been surrounded by a distinct investment 

 of connective tissue and endothelium, we have been able to see 

 endings, which like most of those in the turtle, possessed no 

 capsule, but were distributed free on the primary or secondary 

 tendon groups. While the usual encapsulated form was always 

 found at the musculo-tendinous junction, these free endings 

 were usually found embedded somewhat more deeply in the ten- 

 dinous tissue. In these, however, as well as in the encapsulated 

 forms, the tendon fasciculi differed from the ordinary tendon fas- 

 ciculi in the same way as has been described for the frog and the 

 turtle, staining more deeply and possessing more numerous and 

 more deeply staining nuclei. 



The form and size of the neuro-tendinous end-organs in 

 birds vary according to the number ot nerves which supply 

 them and the part of the organ where the nerves pierce the 

 capsule. Sometimes a meduUated nerve passes along the mus- 

 cle or tendon and, without changing its direction, branches into 



