Twenty Four cases of calculus, which were collected feom the patients, were tested by a serological agglutinin absorption test and the following results were obtained. 1) In all observed xases, blood group specific substances were detected, and this results were agreed with blood group of observed patients. 2) Because the α titer of O-serum is somewhat higher than B, we have come to a conclusion that O type and B type results must be reexamined with much more weighted sample than other type cases.