X] CONNECTIVE TISSUE 75 



rectangular, with deeply stained coarse granules. These 

 are the basophil cells or plasma cells. They are 

 scattered irregularly; they are most numerous amongst 

 and in the neighbourhood of fat cells, and often form a 

 row on either side of the small blood vessels. 



10. Dry film, stained with eosin and methylene blue. Prepare 

 a film as in 8, but let it dry. Treat it like a dry blood film 

 (cp. p. 18) but leave it for 30 seconds in eosin, and 60 seconds in 

 methylene blue. Note (h.p.) the oxyphil leucocytes ; (these are 

 usually better seen in a dry film than in one fixed in alcohol). 



11. Areolar tissue in frog. This may be obtained from the 

 frog instead of from the rat. Cut transversely through the skin 

 of the back of a frog which has been beheaded and held down- 

 ward till the bleeding has ceased. Turn the lower piece of skin 

 downwards, cutting it through at the sides. Connective tissue 

 will be seen stretching from the skin to the body at the level of 

 the posterior end of the urostyle. Cut out a small piece of this 

 connective tissue, and make a film preparation. If the piece of 

 tissue is covered with blood, dab it on blotting-paper ; it may be 

 shaken in salt solution and the excess of fluid removed with 

 blotting-paper, but the leucocytes of the tissue are apt to be 

 altered by the salt solution. The basophil cells in the frog are 

 irregular in shape, often elongated, their granules are of medium 

 size. 



12. Inter-muscular connective tissue of frog. Make a complete 

 transverse incision of the skin of a pithed frog, in the abdominal 

 region. Tear the skin backwards so as to expose the thigh 

 muscles. With forceps lift up the muscles of the ventral 

 surface of the thigh near the knee, and cut away all the muscles 

 over the femur. Place the muscular mass on cork, deep surface 

 uppermost, and gently pull laterally the muscles on either side 

 of the sartorius, a thin layer of connective tissue on either side of 

 the sartorius will come into view. Pin out the muscles so that 

 the connective tissue layer is stretched, wash it with salt solution 



