196 



PRACTICAL HISTOLOGY. 



[xvi. 



(a.) Not only will the sarcolemma be seen, but inside it, here 

 and there, the sarcous substance will be seen cleft 

 transversely into discs (fig. 167, E). 



6. Ending of Muscle in Tendon. This is readily 

 seen by taking the lower end of the sartorius with 

 its tendon from a frog treated as in Lesson XVI. 3, 

 (i.), and which has been afterwards placed in 70 per 

 cent, alcohol. Tease out the muscular fibres, when 

 their conical ends will be seen ending abruptly, and 

 the small tendons beginning as abruptly (fig. 169). 



7. Crab's Muscle (Sarcous Substance) (H). 

 Plunge the living muscles of a crab or better still, 

 use a stag-beetle into absolute alcohol for twenty- 

 four hours. Stain a fragment in dilute eosin-liaema- 

 toxylin, and mount it in Farrant's solution or balsam. 

 In the latter case the clarifying reagent must contain 

 a little eosin to restore the eosin colour to the pre- 

 paration. 



(a.) Observe the fibre striped as in x 



fig. 170, with alternate light and 

 dim discs, the dim discs (a) stained 

 of a logwood tint, while the light 

 discs are of a faint eosin tint. 

 (b.) In the light disc (b) observe a fine line or 

 series of dots running transversely, sometimes called 

 Dobie's line or intermediate 

 6 line (figs. 170, I, 171, c), 

 dividing the light disc into 

 two equal parts, these ad- 

 hering to the ends of the 

 dim disc. They are then 

 called lateral discs. 



(c.) The dim disc may 

 exhibit slight vertical stria- 

 tion, indicating a tendency 

 72 to cleave longitudinally. If 

 transverse cleavage be as- 

 sociated with simultaneous Fl Q f 



FIG. 170. Muscular Fibre of longitudinal cleavage, small Hydrophilus. a. 

 Great Adductor of Rabbit 4. \ 4. i Dim, c. Light 

 Living and Extended, a. elements are Obtained, disc; b Inter- 

 Dim disc; b. Light disc; which were called "sarcous "^ picroc-i?- 



mineand formic 

 glycerine. 



FIG. 169. Rela- 

 tion of a Tendon 

 T. to its Muscu- 

 lar Fibre, the lat- 

 ter with a Coni- 

 cal Termination. 



.# 



171. Fibril 

 Muscle of 



elements " by Bowman, 

 profile. Examined in its /,/ \ Nuclei may be seen. 



own juice, x 300. v / ., * .. 



A similar preparation of 

 an insect's muscle may be stained in picro-carmine 



Tease it so 



