XI.] TENDON. 167 



the fibres of the tendon, while at the same time the logwood stains 

 them. Instead of acid logwood use picro-carmine or acid hsema- 

 toxylin (p. 69). Displace the dye with water and mount in 

 glycerine. The tendons are purposely taken longer than the 

 breadth of the cover-glass, so that they may remain stretched. 



8. Fresh Tendon. On a black surface, tease in normal saline a 

 small piece of any tendon of a calf. Observe the fibres and fibrils, 

 but no cells are visible. Irrigate the preparation with 2 per cent, 

 acetic acid. The mass becomes clear and transparent to the naked 

 eye, and now under the microscope one sees the fusiform nucleated 

 cells singly or in line in order between the swollen-up fibres. The 

 preparation may be stained with magenta, which brings into clearer 

 view the cells, and any elastic fibres present, 



ADDITIONAL EXERCISES. 



9. Tendon of Eat (Dogicl's Method). Very good preparations are obtained 

 by placing the fresh tendons for several days the longer the better in 

 Grenadier's alum-carmine (p. 65). This fluid stains but slowly. The cells, 

 however, are stained, and if a tendon be teased, isolated cells, and cells on the 

 fibres are easily seen. It is a good method for showing the relations of the 

 cells to the fibres. 



10. T.S. Tail of Rat (Corrosive Sublimate and or ax- Carmine). Harden 

 short lengths of the tail of a rat, the skin being first removed, in corrosive 

 sublimate for three hours or so. Remove every trace of the mercuric salt 

 by prolonged washing in alcohol. Stain the tissue in bulk in borax-car- 

 mine, and then decalcify it in dilute hydrochloric acid. Make transverse 

 sections, after embedding it by the interstitial method in paraflin. Sections 

 may also be made by freezing, but they are apt 



to fall asunder. This method also yields 

 beautiful preparations, comparable to those by 

 the gold chloride methods. The transverse 

 .sections of the tendons are very characteristic. 



11. Dried Rat's Tendons. A very convenient 

 method is to dry the tendons of a rat's tail, 

 keeping them extended during the process. 

 After drying, they can then be used at any 

 time. By acting on them with dilute acetic 

 acid they swell up slowly, and the rows of cells 

 are thereby revealed. The cells after washing 

 away the acetic acid can be stained with picro- 

 rnrmine, and the preparation mounted in dilute 



glycerine. 



'12 Cell-Spaces (Saft-CaiMcten) in Central FlQ . I36 ._ C ell-Spaces in the Cen- 

 Tendon (Silver Method). Place the central tral Tendon of the Diaphragm 

 tendon or the whole diaphragm for five minutes of Rabbit. I Lymphatic ; s. 

 in a per cent, silver nitrate. Remove it, and Cell-spaces. Silver nitrate, 

 with a camel's-hair pencil brush both surfaces 



of the tendon to remove the endothelium. Replace it in the silver solution 

 for fifteen minutes. Remove it ; wash it in water, and expose it to light to 



