1907.] Further Studies of Gastrotoxic Serum. 535 



but only weakens its precipitating power for the proteids of stomach cells 

 and blood serum. 



Removal of the Precipitin for the Proteid of Blood Serum. — If the 

 precipitin for the blood serum be removed, the gastrotoxin is still able to 

 precipitate all the three remaining solutions, but not quite to the same 

 degree as before. 



It appears, therefore, that the precipitins of gastrotoxic serum are multiple 

 and to a great extent specific, but that their actions overlap to some extent. 

 The gastrotoxic precipitins for liver-cell and intestine-cell proteids appear to 

 be more nearly allied than the others, if not identical. In confirmation of 

 the above statements I may say that if the blood serum of an immunised 

 rabbit be examined every day, it will be found that the first precipitins to 

 appear in the serum are those for the proteids of the stomach cells and 

 blood serum, and that the precipitins for the liver-cell and intestine-cell 

 proteids appear at a later date during the process of immunisation. 



These results are in agreement with the statement of Nuttall(3) and others 

 to the effect that precipitins are to a large extent, but not absolutely, specific. 



2. The Identity of the Substances producing the Precipitating and Agglutinating 



Reactions. 



The precipitin for stomach-cell proteid was removed from a solution of 

 gastrotoxin in the way described above and the capacity of this solution to 

 agglutinate gastric- cell granules then tested. In order to prove that the 

 precipitin was removed from the solution, a control was in each case prepared, 

 in which stomach-cell proteid was added to the solution instead of gastric 

 granules. 



In this way I have been able to show that in the absence of the precipitin 

 no agglutination of gastric granules occurs, in other words the gastrotoxin 

 does not contain a specific agglutinin for the gastric granules. When 

 unwashed granules are used for the performance of the agglutination test, the 

 gastrotoxin precipitates the albuminous fluid in which the granules float and 

 the latter are agglutinated by this precipitate. When washed granules are 

 used, the gastrotoxin no doubt produces some change of a coagulative nature 

 in the superficial layers of the granules and they are therefore agglutinated 

 as they sink to the bottom. 



On the other hand there is no doubt that the gastrotoxic agglutinin for red 

 blood corpuscles is a specific substance, because if the gastrotoxic precipitins 

 be removed as described above, the resulting solution still agglutinates red 

 blood corpuscles in exactly the same strengths as untreated gastrotoxic serum 

 does. The serum is, of course, heated to 55° for half an hour before 



2 Q 2 



