!•] THE FROG. 127 



a. White fibres ; more or less numerous and dis- 

 posed in wavy bundles. 



/3. The matrix ; a transparent imbedding mass, of 

 sufficient density to resist the pressure of the 

 cover-slip. 



y. Theyellow elastic fibres (a. /3.). Treat with acetic 

 acid; the white fibres disappear, the yellow 

 ones remaining. Note that they occur singly 

 and anastomose, taking a very irregular course. 



8. Stain with magenta. The yellow fibres stain 

 slowly but intensely; their torn ends will fre- 

 quently be seen rolled into a spiral or other- 

 wise contorted, as the result of their elasticity. 



The connective-tissue corpuscles; small nu- 

 cleated cells, variable in size and shape, scat- 

 tered throughout the whole. 



c. Submit a piece of areolar tissue to the action of 

 silver nitrate solution. When it has assumed a 

 deep brown colour, examine in weak glycerine 

 under a high power. The methylene blue process 

 may be here advantageously employed as directed 

 for the tesselated epithelium (§ 2. c). 



a. The matrix ; stained a rich brown, having 

 reduced the silver salt, as did the cementing sub- 

 stance of the epithelium. 



p. The connective-tissue corpuscles; little if at all 

 stained, appearing as a series of irregular white 

 patches {cell spaces). Examine these with care ; 

 each is an irregular branching corpuscle, generally 

 in organic continuity with one or more of its 

 fellows (i.e. the whole tissue is permeated by 

 protoplasmic matter). 



