1895.] MICROSCOPICAL JOURNAL. 2«7 



Vessels. — Inject a frog with silver nitrate, 1 to .300, as 

 has been described for the vessels of the lungs. Fill the 

 bladder with the J alcohol, brash away the epithelium 

 and mount the bladder in balsam, the inner surface up- 

 ward, after exposure to direct sun-light. 



Nerves. — Inject into the bladder lemon juice, then 1 

 per cent gold chloride. Reduce in the I formic acid aud 

 examine flat. Consult, for this manipulation, the techni- 

 que described for the study of nerve endings in the un- 

 striated muscles. 



Sections. — Inject into the bladder 1 per cent osmic 

 acid. In a few minutes, the walls being fixed in an ex- 

 tended state, open the bladder, and put it for -y hour in 

 the osmium solution. Wash, harden in gum and alco- 

 hol ; section, stain with alum carmine, mount in glyce- 

 rine. 



It is very easy to inject the bladder of mammals to 

 fix it in an entended condition. Place the canula in the 

 urethra, and open the abdomen, being careful not to 

 wound the bladder. Force the injection in strongly, and 

 when the distension is sufficient, ligate the base of the 

 organ and dissect out the bladder beyond the ligature. 



Epithelium. — Inject with the i alcohol, and follow the 

 method given for the epithelium of the frog. 



/Sections. — Inject with 95° alcohol and put the organ 

 in 50 centim. of the same alcohol. In 24 hours open the 

 bladder and harden in gum and alcohol. Section, stain 

 in picro-carmine, mount in glycerine. It is necessary to 

 lake the bladder of a recently killed animal, otherwise 

 the epithelial layer will not be present in the sections. 

 The rabbit's bladder is an excellent object for study. 



The Skin. 

 The skin being contractile under the action of rea- 

 gents, it is necessary aftei" it has been properly extended 

 and held in position, to fix it by the methods given for 



