98 PRACTICAL HISTOLOGY [XII 



adductor muscle so that the muscle retracts, and take the 

 anterior yellowish part. 



The nucleus in Coelenterates and Echinoderms is usually on 

 the surface of the muscle cell, it is usually in the muscle sub- 

 stance in Nematodes and Leeches and surrounded by a good deal 

 of sarcoplasm, which may spread out in rays to the periphery. 



Purkinje's cells of the heart. These show as transparent 

 lines and patches under the endocardium, they are most readily 

 obtained from the fresh heart of a sheep. For isolation of the 

 cells, the pieces of endocardium are placed in 33 p.c. alcohol for 

 a day or two, stained with picrocarmine and teased in dilute 

 glycerine. The cells are irregular discs, striated at the periphery. 



Staining unstriated muscle in sections. Place for 10 minutes 

 in 1 p.c. methylene blue (polychromatic), put in water 15 to 

 30 sees., then in 1 p.c. ferricyanide of potassium for 10 minutes, 

 transfer to acid alcohol till sufficiently decolourized, wash in 

 alcohol and mount (Unua). 



