DECALCIFICATION. STAINING IN BULK. 19 



ORGANS (FROG) NaCl. Corr. Inj. 



May 10 7QP- C - Ale. + I. 



,, 11 change to 80 ,, 



,, 12 ,, 90 



,,13 ,, Spt. Meth. 



No. Name 



Draw your pen through each direction as the change is made. 

 The tissues will be ready, at the earliest, in four days for embedding 

 and cutting. Longer exposure to spirit will confer a beneficial tough- 

 ness upon the tissue. 



These and the remaining steps in the preparation of tissues are 

 as far as possible spread over subsequent meetings of the class. 

 In the intervals due attention must be given to the tissues which 

 are in the course of preparation, i.e., changing of fluids, &c. 

 The reagents mentioned, with the exception of absolute alcohol, are 

 provided in the laboratory. 



Decalcification of osseous tissue. 



Place (6) in bone softening fluid (14a, see Appendix). Examine in 24 

 hours, [and as soon as it becomes pliant or feels soft to a needle point 

 introduced into it, wash in changes of water until the colour is removed 

 and after-treat with alcohol. Bones are usually best cut in frozen gum, 

 but this specimen being small will cut well in paraffin. 



Staining 1 in bulk. 



Small pieces are next to be stained in bulk, as follows : cut 

 parallel sided slices or rectangular blocks not more than 3 mm thick 

 (HHHH)) the other dimensions being governed by the nature of the 

 organ. Put one set into a tube with 10 cc h^emalum solution (22) and 

 another into a like quantity of borax carmine (17) in which they 

 remain 48 hours or more, according to their density. The first are then 

 thoroughly washed in water for 12 hours to remove the superfluous 

 stain, and are then placed in 70* )C - alcohol and through increasing 

 strengths to absolute alcohol. They may be ground-stained with eosiii 



