BY DR. LAUDER BRUNTON. 477 



pass their ends through the edges of the wound in the abdo- 

 minal wall in such a way as to fasten the stomach to it, and 

 at the same time to keep the cut edges in apposition. No 

 other suture is required. Leave the canula uncorked for at 

 least half an hour after the operation is finished, for when the 

 dog recovers from the chloroform it will vomit, and if the ca- 

 nula be corked, the fluid contents of the stomach are apt to be 

 forced past the side of the canula into the abdominal cavity. 

 Feed the dog on milk for one or two days, and if the operation 

 be performed in winter, keep it in a place warmed night and 

 day. The da}^ after the operation the edges of the wound will 

 be much swollen, but the swelling will subside in a day or two. 

 After the wound has begun to heal, the cicatrix may thicken, 

 and the outer plate of the canula begin to press too much on 

 the skin, so that it ulcerates. If this should occur, the canula 

 must be lengthened by screwing the two Hangs further apart. 

 The canula may be closed by an India-rubber stopper, or by a 

 cork. If the dog tears out the cork with his teeth, soak it in 

 decoction of colocynth, or put a little phosphoric acid on its 

 outer end. 



In order to collect the juice, let the animal fast for several 

 hours, so that its stomach may be quite empty, but not for 

 more than a day, as the mucous membrane would become 

 covered with a thick coating of mucous. Let an assistant pat 

 the dog, and keep him quiet ; withdraw the cork from the 

 canula, and tickle the inside of the stomach with a feather tied 

 to a glass rod. Put a small beaker underneath, so that the 

 end of the rod rests on its bottom : the gastric juice will flow 

 into it down the sides of the rod. 



** 105. Examination of Gpstric Juice. The gastric 

 juice is thin, almost colorless, very faintly opalescent, and has 

 a faintly acid taste. Its specific gravity is nearly the same as 

 that of water. Its reaction is strongly acid; blue litmus paper 

 becoming bright red when dipped into it. 



Composition. In the dog, it contains three per cent, of 

 solids ; in man, only one per cent. About two-thirds of this 

 is organic matter, consisting of pepsin and peptones ; and one- 

 third of indVganic matter, consisting of chlorides of potassium, 

 sodium, ammonium, calcium, and phosphates of calcium, mag- 

 nesium, and iron. The specific gravity and amount of solids, 

 organic and inorganic, are to be determined in the same way 

 as those of saliva. 



The acidity of the gastric juice is really due to free acid, 

 and not to acid salts. To show this, the amount of bases and 

 of acid contained in it must be determined. When this is 

 done, it is found that the quantity of acid is more than sufli- 

 cient to form acid salts with all the bases present which are 

 capable of forming such salts ; it must, therefore, exist partly 



