234 Dr. C. Bolton. Further Observations on the [Nov. 16, 



I. Production of a Gastrotoxin Active against the Cat. 



1. Method. — The gastric cells of the cat were periodically injected into 

 another animal, the blood of the latter gradually l^ecoming poisonous for the 

 cat's gastric mucous membrane. In this way I have endeavoured to immunise 

 the rabbit, fowl, and goat. The rabbit and fowl proved very difficult animals 

 to work with, as they very readily succumbed to the injections and could 

 only resist very small doses. 



Immunisation of the Goat. — I found that the goat was quite a suitable 

 animal, and that it produced a very powerful gastrotoxin for the cat. 

 Subcutaneous injections of cat's stomach cells were given at intervals of 

 7 to 10 days. The development of the immune substances in the blood 

 of the goat is the same as I have before described in connection with the 

 guinea-pig-rabbit gastrotoxin. 



At first I injected the cells themselves, but found that abcesses were 

 liable to result. I then tried an emulsion of cells in a solution of salicylic 

 acid with a similar result. I now use a fresh dilute saline extract and give 

 50 c.c. for a dose. This very rarely produces suppuration if due care be 

 exercised. The injections are given as I have described before, and the goat 

 is bled from the ear if a small quantity of blood be required, but from the 

 jugular vein witli a cannula if a large quantity be needed. 



I have used the blood serum so obtained as a means of producing an ulcer 

 of a definite size and in a definite position in the cat's stomach. 



2. Effects of Local Injection of the Serujn. — The method of local injection 

 into the cat's stomach wall is the same as I described in connection with 

 the guinea-pig. The animal is anaesthetised with ether and the abdomen 

 opened under antiseptic precautions. The stomach is drawn out and a 

 hypodermic needle inserted between the mucous and peritoneal layers of the 

 stomach. The serum is slowly injected with a 10-c.c. glass syringe. A local 

 codema is thus produced which forms a button-like tliickcniug in tlie wall and 

 projects into the lumen of the stomach as a rounded elevation. 



If cut across, the iluid appears to be infiltrating the muscular coat. I have 

 tried injections between the muscular and peritoneal coats and also between 

 the muscular and mucous coats, but tbe result always appears to be the 

 same, and I liave not found it possible to destroy definite layers of the 

 stomach wall in tiiis way. It might be possible to do so in the case of a 

 larger animal. 



The amounts I have injected are from 5 to 10 c.c. T now eni])loy 6 or 

 7 c.c. when I wish to pi'oduce an ulcer. The serum is rajjidly absorbed, and 

 apparently soaks into tli(! overlying mucous membrane, which is then 

 digested by the gnsti ic; juice. In all the following experiments the serum 



