1909.] Pathology of Gastric Ulcer. 235 



was injected about the middle of the anterior wall at the cardiac end of the 

 stomach. The animals, as a rule, do not eat well for a day or two, and may 

 vomit once or twice and lose a little weight, but they soon recover and do 

 not appear to suffer from any symptoms. 



Formation. — The part of the mucous membrane affected sloughs, and by 

 the third to the fifth day a clean ulcer results, which may involve the 

 mucous membrane only, or may extend through the submucous and muscular 

 coats. The depth depends upon the strength of the serum and upon the 

 condition of the contents of the stomach. Perforation of the ulcer and 

 resulting peritonitis occasionally occurs. ^ 



The acute ulcer so formed has cleanly defined margins and base, and is 

 rounded or sometimes more irregular in shape. The whole of the area of 

 muscular coat exposed may have disappeared or only a portion of it. In 

 short, the ulcer presents the typical punched-out appearance of the acute 

 gastric ulcer of man. 



3. Mode of Action of the Scrum. — As I have said, the action is a toxic 

 one. The serum causes changes in the cells of the overlying mucous 

 membrane, which is then digested by the gastric juice. That the action is 

 not a mechanical one I have proved by injecting neutral fluids, as I have 

 described previously in the case of the guinea-pig. 



Ten cubic centimetres of cat's serum may be injected into the stomach 

 wall, and whether the stomach is resting or digesting the serum is com- 

 pletely absorbed, and no ulcer results. Further, the effect produced on the 

 stomach and the extent of the ulceration depend upon the stage of immunisa- 

 tion to which the goat has reached. So that there is a definite poison in the 

 serum which directly affects the gastric cells in the same way as the guinea- 

 pig-rabbit serum affects the cells of the guinea-pig. 



4. Dependence of the Extent of Ulceration iqjon whether the Stomach is 

 Resting or Digesting. — The necrotic lesions in the gastric mucous membrane 

 being dependent upon the action of the gastric juice, it would appear that 

 when the gastric glands were resting and the stomach empty the lesions 

 should fail to appear or at all events be less marked than when the organ 

 contained food, unless the gastrotoxin has the power of exciting secretion, 

 a point which I have not yet investigated. I did a series of experiments 

 on guinea-pigs, half the animals being starved and half fed, to settle this 

 question, and found that I was unable to do so, because it is practically 

 impossible in my experience to obtain a guinea-pig with its stomach 

 absolutely empty. These animals will not live very long without food, and 

 24 hours after feeding the stomach contains a fair amount of highly acid 

 fluid with food remnants. 



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