246 ELEMENTARY BIOLOGY. [XIII. 



body, mixed with other tissues. Tease out a bit 

 of fresh tendon in water: examine with a high 

 power. 



a. It is chiefly made up of very fine wavy fibres 

 which run in bundles parallel to one another ; 

 they have an ill-defined outline and do not 

 branch. 



/3. Treat with dilute acetic acid. Most of the 

 fibres disappear, but a few well defined curled 

 fibres {yellow elastic fibres, see h) remain. Be- 

 sides these some elongated granular proto- 

 plasmic masses are brought into view {con- 

 nective-tissue' corpuscles) . 



h. Yellow elastic tissue. This does not occur in large 

 collections, in the pure form, in the frog ; although 

 mixed with white fibrous and other tissues, it is 

 very widely distributed. 



a. Tease out in acetic acid some of the bands of 

 tissue beneath the frog's skin ; examine with 

 a high power. Numerous fine well-defined 

 , branched fibres, running in bold curves, will be 

 seen : these are yellow elastic fibres, as the 

 acetic acid {a. /S) destroys the white fibrous 

 tissue. 



e. Striped muscle, 



a. Tease out gently a bit of muscle which has been 

 kept in alcohol, and examine with 1 inch obj. 



a. Composed of elongated fibres, which exhibit 

 a tendency to split up into finer filaments 

 {fibrillcB). 



