2 EXEECISE I 



standard and blow some air ^ through the Einger-Locke solution in the 

 beaker. 



II. Dissection. In the carcase of the freshly-killed rabbit, provided for 

 you in the tray, open the abdomen freely in the mid-line and excise with 

 scissors about 10 cm. length of small intestine, emptying it by gentle 

 pressure with the fingers before excising it. The duodenum usually affords 

 a better preparation than the ileum ; but the piece should not be taken from 

 quite close to pylorus. Place it in cold Ringer-Locke fluid. Also the 

 spleen ; also a piece of the thoracic aorta about 5 cm. long. Take care in 

 excising these to handle them with as little damage to them as possible. 



Obs. 1. III. From the length of small intestine lying in the cold ' Ringer-Locke ' 



Intestinal move- ^^^ Qf^ with sharp scissors by two clean cuts a piece 2 cm. long. It will measure 

 longer when it is relaxed. Holdicg this gently with the fingers, pass through 

 its wall about 3 mm. from the cut edge a needle carrying a thread. Withdraw 

 needle and by the thread tie the gut closely down to the taper bent end of the 

 glass tube affixed to the table-standard. Attach a pin-hook and thread through 

 the lip of the opposite end of the intestine. 



Place the piece of intestine thus attached to the glass tube in the beaker 

 of cold Ringer-Locke fluid so that intestine is wholly plunged; clamp glass 

 . tube in position on the vertical standard. Bring the shorter arm of the 

 writing lever vertically over intestine; slip over it a non-slip loop of the thread 

 from intestine. Nearly counterpoise lever (with a small lump of clay, 

 w, text -fig. 1) so as to allow ' tonus ' as well as ' beat ' of intestine to show. 



See that the glass style (p, text-fig. 1) at end of lever's long arm — which 

 may have with advantage a length of 30 cm. — marks at all heights on drum 

 surface and over a considerable arc. Place a small low gas-flame under the 

 outside beaker which serves for water-bath to the inner beaker. 



Start the recording drum ; note movements of intestine, beginning when 

 thermo meter in inner beaker indicates about 30° C. Later, when bath is at 

 35° C, withdraw the gas-flame. The beats will be about 10-20 a minute. 



Obs. 2. ^^' -^^^ "^ ^'^' ^^ solution of 'adrenalin* (i.e. adrenal extract) 01 per 



Adrenal extract cent, to the Ringer-Locke fluid (about 300 cc.) in the beaker. Note the effect 



on intestinal /^x ^^ ^j^ ^ ^^^^ ^^^ (2) on the tonic length of the strip. Note the slight pink 



movement and , . __ i -i t ? • 



tone. colour gradually tinging the solution. [Try the ileocolic sphincters 



contraction with adrenalin.] 



Obs. 3. V. Empty and rinse out the inner beaker. Refill it with cold 



Adrenal extract Ringer-Locke fluid and blow some air through as before. Fix a strip of 

 on spleen. 



