Toxic broth filtrates of one A, one B, six C, and one D types Cl. botulinum, and the antitoxins produced by injecting these filtrates into goats have been tested, from the standpoint of working out the antigenic "make up" of the toxins. The results obtained indicate:-
(1) The A and the B types are monospecific.
(2) The C types contain three components (a) C₁ , (b) C₂ , and D. The D fraction is contained in only very slight amount.
(3) The D type contains chiefly the D, but also a small quantity of the C fraction.