ISO THE TISSUES. 



lost, the naked axis-cylinder further dividing into two, three, or four 

 branches, each of which runs along on the intrafusal fasciculi, giving 

 off numerous short, irregular side branches, which partly enclasp 

 the tendon fasciculi and end in irregular end-discs. Some of the ter- 

 minal branches pass between the smaller fibrous tissue bundles of 

 the fasciculi, ending between them. 



In these end-organs, the larger nerve-branches are found near 

 the center of the bundle of intrafusal tendon fasciculi, the terminal 

 branches and the end-discs nearer their periphery. The neuroten- 

 dinous nerve end-organs are widely distributed, being found in all 

 tendons although not equally numerous in all. Like the neuromus- 

 cular nerve end-organs, they are especially numerous in the small 

 tendons of the hand and foot. Sensory nerve end-organs, which 

 resemble in structure the neurotendinous end-organs here described, 

 though somewhat smaller than these, have been found in the tendons 

 of the extrinsic eye-muscles. 



In this brief account of the mode of ending of the telodendria of 

 the dendrites of peripheral sensory neurones (sensoiy nerve-fibers) 

 it has not been possible to discuss any but the more typical varie- 

 ties of sensory nerve -endings. Other nerve -endings will be consid- 

 ered in connection with the several organs to be treated later. For 

 a fuller discussion of this subject, the reader is referred to special 

 works and monographs. 



TECHNIC. 



Fresh medullated nerve-fibers, when teased in an indifferent fluid, 

 show the peculiar luster of the medullary sheath, and also the 

 nodes of Ranvier, the neurilemma with its nuclei, and the segments 

 of Lantermann. At the cut ends of the fibers, the typical coagula- 

 tion of their medullary portions is seen in the form of drops of myelin. 

 All these structures can also be seen after using i oJ osmic acid. A nerve 

 (not too thick) is placed in a i % aqueous osmic acid solution, then 

 washed for a few hours in distilled water, and finally carried over into 

 absolute alcohol. After dehydration, small pieces are cleared with oil of 

 cloves and the fibers teased apart upon a slide. The medullary sheath is 

 stained black and hides the axial space, the nodes are clear, the neu- 

 rilemma is sometimes seen as a light membrane, and the nuclei of the 

 fibers are of a lenticular shape, and stained brown. 



The nodes of Ranvier may also be demonstrated by means of 

 silver nitrate solution. Fresh nerve-fibers are either teased in distilled 

 water to which a trace of i% silver nitrate solution has been added (the 

 nodes of Ranvier appear after a short time as small crosses), or whole 

 nerves are placed for twenty-four hours in a 0.5% aqueous solution 

 of silver nitrate, washed for a short time with water, hardened in 

 alcohol, after which they are imbedded in paraffin and cut longitudinally. 

 Exposure to light will soon bring out the ' ' crosses of Ranvier ' ' at the 

 nodes. The appearance of these crosses is due to the fact that the 

 silver nitrate solution first penetrates at the nodes of Ranvier, and then 

 passes by capillary attraction along the axial cord for some distance. 

 After the reduction of the silver, the cruciform figures appear colored 



