Mi:S('l,K A\D TKNMOX (NERVR-BNPINGS). 343 



tic the frog's thiglis together.) Now open the frog, ligature 

 the intestine above the bladder, and cut away the abdomen 

 so as to have in one piece bladder, rectum and hind legs. 

 Put tliis into gold solution of 1 : 2000 for four hours ; the 

 bladder is then excised, slit open, and pinned (witli hedge- 

 hog spines) on to a cork (outside downwards). Place it 

 under running water until all the epithelium is washed away. 

 Use a carnel's-hair brush if necessary. Put for twenty-four 

 hours into gold solution of 1 : 6000. Wash in pure water, 

 and put away in the dark " for some time " in acidulated 

 water, and finally reduce in fresh water in daylight. 



RANVIEB (Traite, p. 854) recommends his two gold pro- 

 cesses, the liquids being injected as above. 



GKUN STEIN (Arch. inik. An at., 1899, p. 1) injects 1 per 

 cent, methylen blue in normal salt solution through the vena 

 abdouiinalis, and after twenty to thirty minutes excises the 

 bladder and exposes to the air. Fix the stain with picrate 

 of ammonia and mount in glycerin with the same ( 343). 



