Abstract
Ricin, a highly toxic protein, showed not only a pyrogenic activity but also a strong hemorrhagic activity in rabbit skin. Its activity was due to increased permeability of the blood vessel and therefore, it was more clearly demonstrated with 0.5% solution of Trypan blue, and this permeability was characterized by a long latent period and duration. Ricin had no caseinolytic activity or esterase activity using N-benzoyl-L-arginine ethyl ester and N-acetyl-L-tyrosin ethyl ester as substrates. These results suggest that ricin has a powerful inflammatory effect, but it is not an "inflammatory protease".
