220 PRACTICAL HISTOLOGY. 



cultj in all parts of either the small or the large 

 intestine. It is preferable to choose an animal (e.g. 

 rabbit or guinea-pig) in which the intestinal coats 

 are not very thick. The following is the mode of 

 procedure: A piece of glass tubing about a quarter 

 of an inch in diameter and five or six inches long 

 is taken, and one end is drawn out into a canula, 

 whilst to the other a small piece of India-rubber 

 tube, furnished with a spring clip, is attached. 

 Chloride of gold solution (J per cent.) is drawn up 

 into the tube so as almost to fill it, and the clip 

 is then closed, to prevent the escape of the fluid. 

 Care should be taken not to suck any of the 

 gold solution into the mouth. A piece of intestine 

 about three inches long is removed from the dead 

 animal, and if not already empty its contents are 

 washed out by a stream of salt solution. The intes- 

 tine thus emptied and cleaned is ligatured firmly at 

 one end, whilst into the other is tied the canulated 

 end of the glass tube containing the gold solution. 

 When thus secured the clip is opened and the fluid 

 is allowed to flow into and distend with moderate 

 force the piece of gut, the action of gravity being 

 assisted by gently blowing through the India-rubber 

 tube. As soon as the intestine is filled with the 

 gold solution the clip is again allowed to close, and 

 then, while an assistant holds the glass tube in a 

 vertical position, the operator ligatures the gut just 

 beyond the end of the canula, which may not be cut 

 away. The piece of intestine, thus filled with the 

 gold solution, is immersed for an hour in more of 

 the same liquid. It is then placed in a dish of 

 water and cut open longitudinally with scissors, so 

 as to allow the contained fluid to escape, after which 

 the puckered, ligatured ends may also be removed. 

 The tissue being hardened by the gold solution, the 

 piece of gut which remains retains its cylindrical 

 shape. It is well to halve it by another longitudinal 

 cut, so that both inner and outer surfaces may be 

 freely exposed to the light. The pieces are now 

 placed, with their outer surfaces uppermost, in a 



