102 



PRACTICAL PHYSIOLOGY. 



[XIV. 



ADDITIONAL EXERCISES. 



7. Muscle-Plasma. Kill a rabbit by bleeding from the carotids, open the 

 abdomen, insert a cannula in the aorta, and wash out all the blood from the 

 lower limbs by means of a stream of cold saline solution (0.6 per cent., 

 NaCl). The solution is made cold enough by placing lumps of ice in it. 

 Skin the limbs quickly, cut o!t' pieces of the muscle and plunge them into a 

 mixture of salt and ice (i - 2 C.), where they quickly become quite hard and 

 frozen. When they are frozen remove them from the mixture, wipe them 

 with blotting-paper, and place them on a plate kept cold by ice and salt 

 mixture. Cut them into fine slices (cutting parallel to the direction of the 

 fibres). Wrap the slices in linen and squeeze them in a pair of cooled enamelled 

 iron lemon-squeezers ; a yellowish, viscid alkaline plasma is obtained, which 

 sets in the course of an hour or so into a solid jelly, with the simultaneous 

 appearance of an acid reaction. By-and-by a clear clot of myosin and a fluid 

 muscle-serum is obtained, just as in a blood-clot. The muscle-plasma con- 

 tains several proteids. For full details of these see Halliburton, Journal of 

 Physiology, viii. p. 133. 



8. Halliburton's Researches on Proteids of Muscle. With a stream of 

 normal saline solution wash out the blood-vessels of a rabbit just killed. Do 

 this by placing a cannula in the aorta. Remove the muscles quickly, chop 

 them up and extract for a day with 5 per cent, solution of magnesium sul- 

 phate. This is done by the demonstrator. Use this fluid. 



(a.) It is probably acid due to lactic acid. Test for this (p. 78). 

 (b.) Coagulation. Dilute some with 4 vols. of water, divide it into two 

 parts, keep one at 40 C. (rapid coagulation) and the other at the ordinary 

 temperature (coagulation, but slower). Clot of myosin formed in both. 



(c.) Remove the clotted myosin from (b.} ; it is readily soluble in 0.2 per 

 cent. HC1, forming syntonin ; and also in 10 per cent, sodium chloride. 



(d.} Add a few drops of 2 per cent, acetic acid to some of the extract = 

 stringy precipitate of myosinogen. 



(e.) Perform fractional heat coagulation (Halliburtoii), p. n. 



" (i.) With the original extract coagula are obtained at 47, 56, 63, 73 C. 

 " (ii.) With liquid (salted muscle-serum) from (>.), after separation of the 



clot, coagula are obtained at 63 and 73 C. 



"(m-) With muscle-extract which has been saturated with MgS0 4 and 

 filtered. The globulins are thus separated. " Coagulation now occurs 

 at 73 C., but the coagulum is small." 

 The following table from Halliburton shows these facts : 



9. Pigments of Muscle. 



(a.) Notice the difference between the red (semi-tendinosus) and pale muscles 

 (adductor magnus) of the rabbit. 



(6.) The muscular part of the diaphragm shows the spectrum of oxy-hfiemo- 

 globin, even after the blood-vessels have been washed out by salt solution 

 (Kiihne). 



