INNERVAT10N OF BLADDER OF FROG. 303 



Smooth Muscle. 



638. Smooth Muscle, Isolation of Fibres (SCHWALBE, Arch.f. 

 mile. Anat., 1868, p. 394). Maceration in weak chromic-acid 

 solution. (0'02per cent, proved a generally useful strength.) 

 This is a better reagent than osmic acid, 1 per cent, acetic 

 acid (Moleschott), weak sulphuric acid, pyroligneous acid 

 (Meissner), 20 per cent, nitric acid (Reichert), 32 to 35 per 

 cent, potash solution (Moleschott), as it preserves better than 

 any of these the finer structure of the cells. 



GAGE'S methods (see Journ. Roy. Hie. Soc., 1887, p. 327). 

 MOBIUS, liquid for maceration of the muscle of Cardium (see 

 above, 512). 



639. Bladder of Frog, Innervation of (WOLFF, Arch.f. mik. 

 Anat., 1881, p. 362). A frog is killed and a solution of gold 

 chloride of 1 '20,000 injected into the bladder through the 

 anus. (If the injection flows out on removal of the syringe, 

 tie the frog's thighs together.) Now open the frog, dissect 

 away the attachments of the bladder, ligature the intestine 

 above the bladder, and cut away the abdomen of the frog so 

 as to have in one piece bladder, rectum, and hind-legs. (All 

 this time the bladder must be kept moist with weak gold- 

 solution.) The bladder and the rest are now put into gold- 

 solution of 1*2000 for four hours; the bladder is then ex- 

 cised, slit open, and pinned (with hedgehog spines) on to a 

 cork (outside downwards). Place it under running water 

 until all the epithelium is washed away. Use a pencil 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 common day light. The muscles should be pale blue- 

 red ; medullated nerves dark blue-red ; sympathetic nerves 

 and ganglia carmine-red. EANVIER (Traite, p. 854) recom- 

 mends one or the other of his two gold-processes. The 

 bladder of frogs should be carefully distended by injection of 

 the lemon- juice or gold chloride and formic acid through the 

 cloaca. 



640. Musculus dilatator pupillae (DooiEL, Arch.f. mik. Anat., 

 1886, p. 403). An enucleated eye is divided into halves and 

 the anterior one with the iris brought for some days into a 



