434 



Dr. C. Bolton. On the 



[Jan. 25, 



II. Specificity of G-astrotoxin. 



If this serum be strictly specific for the stomach cells of the guinea-pig, it 

 should possess chemical affinities for the stomach cells alone and for no other 

 tissues of the body. On injection into the guinea-pig it would then produce 

 lesions limited to the stomach, and would also be rendered inactive by 

 mixture with stomach cells, which would combine with the poisonous 

 substance in the serum and take it out of solution. Further, other tissues of 

 the body should not possess chemical affinities corresponding to those of the 

 stomach cells and, therefore, would not render the serum inactive by mixture 

 with it, and sera formed against those tissues would not produce lesions in 

 the stomach on injection. 



The specificity has therefore been tested by comparing the relative power of 

 different cells of the body of the guinea-pig to render the serum inactive, and 

 also by comparing the effects of the serum with those of a hepatotoxic, an 

 enterotoxic, and a hsemolytic serum obtained by injecting blood. 



The experiments have been conducted in vivo and in vitro. 



1. Poiver of Different Cells to Sender the Serum Inactive. 



In my former communication I gave the results of a few experiments. I 

 have since examined this question more extensively and although the subject 

 is far from being completed yet I will here give the results of my further 

 investigations. 



In mixing the various cells with the serum to be examined, care must be 

 taken that enough cells are present to saturate the serum otherwise when 

 they settle to the bottom of the tube a portion of the serum is left unexposed 

 to their action. The cells obtained by scraping the mucous membrane of one 

 guinea-pig's stomach are enough to saturate 4 c.c. serum, but the resulting 

 mixture will not yield 4 c.c. serum back. For a reliable experiment it is 

 necessary to inject at least 10 c.c. serum and, therefore, to obtain this I take 

 12 c.c. serum and mix with it the mucous membrane of three guinea-pigs' 

 stomachs. After centrifugalisation it is quite easy to obtain 10 c.c. of treated 

 serum. 



The cells of the mucous membrane of the small intestine are obtained in 

 the same way as those of the stomach. 



The liver is pounded up and passed through a tea strainer in order to 

 prepare it. In all cases the blood is washed out of the organ in question 

 before it is removed from the body. 



If the serum is examined in vivo after such treatment a control animal is, 



