60 ELEMENTARY PHYSIOLOGY. [V. 



in all directions. Some small elastic fibres 

 running singly will also be seen, their out- 

 lines are more distinct than those of the bun- 

 dles of white fibres ; they sometimes branch 

 and sometimes anastomose where they cross 

 one another. Where the film is well stretched 

 the elastic fibres run for the most part quite 

 straight, elsewhere they are curled at their 

 ends and have a more or less sinuous course. 

 If there is any doubt as to which fibres are 

 elastic, irrigate with acetic acid, cp. (6). 

 d. To make evident the corpuscles, take a 

 rather large piece of the film and let the 

 edges partially dry so that it may stick to 

 the glass slide ; add a drop or two of a strong 

 solution of Spiller's purple in water or in 30 

 p.c. alcohol, in a few minutes wash away the 

 excess of the purple with water from a pi- 

 pette, and mount in water. 



B. CONNECTIVE-TISSUE CORPUSCLES. 



1. Take a piece of the thin expansion of a tadpole's 

 tail preserved in chromic acid *2 p.c. Gently 

 break up a piece in glycerine. Where the hex- 

 agonal cells of the epidermis have broken away, 

 the homogeneous matrix may be seen, imbedded 

 in which are many blood-vessels and a number 

 of stellate cells. 



The larger dark stellate cells are pigment-cells, 

 the smaller stellate cells are connective-tissue 

 corpuscles, each of which consists of a nucleus 

 and a branched protoplasmic body. Their pro- 



