STRUCTURE OF MUSCLE. 79 



LESSON XVII. 



CONNECTION OF MUSCLE WITH TENDON; BLOOD- VESSELS OF 

 MUSCLE; CARDIAC MUSCULAR TISSUE; DEVELOPMENT OF 

 MUSCLE; PLAIN MUSCULAR TISSUE. 



1. To study the connection of muscle with tendon, a frog is killed by de- 

 struction of the brain and spinal cord, and placed in about a litre of water raised 

 to a temperature of 55 C. It is left in this for 15 minutes, the water 

 gradually cooling. It is then easy to dissociate the muscular fibres in large 

 numbers. To observe their attachment to the tendon-bundles a fine longi- 

 tudinal shred must be snipped off with scissors at the tendinous attachment, 

 and dissociated upon a slide in a drop of water. It will usually be found 

 that the muscular substance is retracted from the end of the sarcolemma 

 tube, which is firmly cemented to the tendon bundle. The structure may be 

 brought more distinctly into view by adding to the dissociated fibres a drop 

 of a weak solution of iodine in salt-solution or in serum (iodised serum). 1 

 To preserve the specimen, mount it in dilute glycerine coloured by magenta. 



2. The blood-vessels of muscle. These are to be studied in longitudinal 

 and transverse sections of injected muscle. It will be noticed that the capil- 

 laries are very numerous, and form a network with oblong meshes. In the 

 red muscles of the rabbit, small dilatations are seen on the transverse cords 

 of the network. 



3. The muscular tissue of the heart is studied in sections of that organ 

 arid also in teased preparations. To prepare the latter, place a small piece 

 of heart-muscle in 30 per cent, alcohol for a few days : stain in picro-carmine 

 solution (see Appendix) for some hours ; and tease in dilute glycerine. 



4. Tear off a small shred of the muscular coat of a piece of intestine which 

 has been from 24 to 48 hours in per cent, bichromate of potash solution. 

 Hold the shred with forceps in a drop of water and fray it out with a needle. 

 In this process many cells will be set free and can be seen with a low power. 

 The preparation may then be covered and examined with a high power. 

 Sketch one of the cells. Then allow hsematoxylin solution to pass under the 

 cover-glass and lastly a drop of glycerine. Sketch another cell after staining. 

 Measure two or three cells and their nuclei. 



Ending of muscle in tendon. A small tendon-bundle passes to 

 each muscular fibre and becomes firmly united with the sarcolemma, 

 which extends over the end of the fibre (fig. 91). Besides this immed- 

 iate attachment, a further connection is established by the fact that 

 the areolar tissue between the tendon-bundles is continuous with that 

 which lies between the muscular fibres. 



1 This method is the one given by Kanvier (Traite Technique, 2me edition, p. 395). 

 The muscle-endings may also sometimes be well seen at the extremities of the tendons, 

 which are removed from the mouse's tail in the manner described in Lesson X., p. 45. 



