BY DR. LAUDER BRUNTON. 491 



diately and dissect off part of the muscular layer from the 

 proventriculus, which lies between the crop and gizzard. The 

 ends of the gastric glands are thus laid bare. With a pair of 

 curved scissors snip offthe ends of the glands, taking care not 

 to cut much below the surface. Squeeze the shred so obtained 

 'between two bits of blue litmus paper. It will have a neutral 

 or at most an extremely weak acid reaction, while the inside 

 of the stomach will be found to be strongly acid. The pres- 

 ence of pepsin in the part of the glands where little or no acid 

 is contained may be shown by dissecting oft' this part along 

 with the muscular layer, and placing it in a test-tube with 0.1 

 per cent, hydrochloric acid in the water-bath at 40 C. Part 

 at least of the muscular layer will be digested. The presence 

 of acid only on the surface of the stomach can be shown, also, 

 by injecting first a solution of half a gramme of ferric lactate, 

 and then a solution of potassium ferrocyanide into the jugular 

 vein of a rabbit, killing it about an hour afterwards, and open- 

 ing the stomach immediately. These two salts form Prussian 

 blue only in the presence of an acid. On making a section of 

 the wall of the stomach, it is seen that the blue color is en- 

 tirely confined to the surface, the deeper part of the mucous 

 membrane remaining colorless. 



After Death Acid continues to be formed in the Glands. 

 Thus, if the stomach of a pig or rabbit is cut in pieces, washed 

 until it no longer gives a trace of acid reaction, and then left 

 to itself, it is found after a time to be again acid. 



* 128. Digestion of the Stomach by itself. If there 

 is only a small quantity of acid present in the stomach it will 

 not be completely digested after death ; but if it contains 

 anything which will supply acid, not only the stomach, but a 

 great part of the adjoining organs may be digested. Give a 

 cat a quantity of milk, or introduce the same liquid into the 

 stomach of a rabbit or guineapig by means of a syringe and a 

 gum-elastic catheter. For this purpose a perforated cork 

 should be placed between the animal's teeth, and the catheter 

 passed through the hole into the stomach. In an hour after kill 

 the animal, and let it lie in a warm place for twenty-four hours. 

 The whole of the stomach will probably be found digested. 

 The stomach is not digested during life, because the alkalinity 

 of its walls is preserved by the circulation of blood in them. 



* 129. Digestion of the Stomach during Life. When 

 the circulation of the blood is arrested in one part of the organ, 

 it becomes digested, and ulceration occurs. This is best shown 

 by Sharpey's modification of Pavy's original experiment. The 

 method consists in opening the stomach of a rabbit, narcotized 

 by subcutaneous injection of chloral, by a longitudinal incision, 

 seizing a part of its posterior wall with a pair of artery forceps 

 and drawing it forward. This having been done, a ligature is 



