86 



in from I to 3 days ; test at intervals with needles to ascertain 

 whether the fascicles and fibers can be easily separated ; or frag- 

 ments may be shaken in a test tube or vial with water in order to 

 separate the fibers. 



When the dissociation is sufl&cient pour ofi^ the acid and wash 

 the muscle gently but thoroughly with water. If the tissue is to be 

 stained with hematoxylin or carmine, or kept for any length of 

 time, drain off the water and add a half- saturated solution of alum. 

 For permanent storage, pour off the alum solution and place suc- 

 cessively in 6j% and 82% alcohol. 



For temporary examination, tease out a portion of the muscle in 

 water, separating the fibers carefully by means of needles ; cover 

 and examine. 



§ 13. Permanent preparations, (a) unstained. After teasing 

 out with the needles drain off the water and add a small drop of 

 glycerin or glycerin jelly ; cover, and seal after first properly clean- 

 ing (§§ iio> III)- i.b) stained. Either before or after the final 

 teasing stain with picric alcohol, picrofuchsin (for relation of muscle 

 fiber to tendon), or after the alum solution with hematoxylin or car- 

 mine. Wash away the staining fluid with water and mount (a) in 

 glycerin or glycerin jelly (§ 104, 105), or (^) dehydrate, clear, and 

 mount in balsam (§ 107 + ). 



§ 14. Caustic potash dissociator.* Formula : Caustic pot- 

 ash, potassium hydroxid (in sticks), 35-40 grams ; distilled water, 

 65 or 60 c.c. This solution will be used for the isolation of cardiac 

 muscle cells, although it may be used for striated or plain muscular 

 tissue, or as a general dissociator. It may also be employed for iso- 

 lating the cells of hair, horn or nail, either full strength or diluted. 



§ 15. Directions for use. Place in the fluid small pieces of the 

 heart muscle of a fetal, new-born or young animal ; after 10 or 15 

 minutes, the tissue should be tested with needles at intervals of 

 about five minutes, so that the action may not be too prolonged ; 

 probably 15-30 minutes will suffice. As soon as the elements sepa- 

 rate readily, pour off the caustic potash solution and add an abund- 

 ance of bo% solution of potassium acetate (potassium acetate, 60 

 grams ; distilled water, 40 c.c). Take small fragments and tease 

 them in this solution, or shake them in a vial, until the cells are sep- 

 arated from each other. 



* See note on page 85. 



