MEDICAL AND BIOLOGICAL STAINING TECHNIQUES 



C. Solution A . . . . • • 25 ml. 



Solution B . . . . . . 8 ml. 



Note: This solution must be freshly prepared as 

 required. 



Technique: 



Tissues should be fixed not longer than two to three hours in 

 5% formalin, or frozen sections of fresh material may be employed. 



1. Rinse with distilled water from four to five seconds; then 

 immerse in Solution C for three to four hours, controlling under 

 the microscope at intervals, until melanoblasts are stained black. 



Note: This solution is likely to overstain if it becomes sepia 

 brown. 



2. Wash with distilled water; dehydrate; clear; mount. 



Result: 



Melanoblasts, black. 



Note: After dehydration (in Stage 2) 1% crystal violet in abso- 

 lute alcohol may be employed as a counterstain, if desired. 



ELASTIN STAIN 



(Weigert) 



Any fixative may be used except Susa, and tissues may be em- 

 bedded in paraffin wax or in Celloidin or in L.V.N. 



Preparation of the Staining Solution: 



Triturate i gm. of Weigert elastin stain and 5 gm. clean, dry 

 silver sand with 100 ml. absolute alcohol and 2 ml. pure hydro- 

 chloric acid until all the stain has gone into solution; then filter. 



Note: The staining solution deteriorates after two or three 

 weeks. 



The nuclei may be stained with Orth's lithium carmine prior to 

 the following procedure if no other counterstain is desired. 



Technique: 



I . Sections are brought down to 90% alcohol and stained one half 

 to twelve hours according to depth of staining desired. The slides 



96 



