The action of venom and proteolytic enzymes on the non-specific inhibitor of hyaluronidase.

1. It has been shown that a number of proteolytic enzymes and snake venom, in relatively small amounts, and within a wide range of pH variation, will restore hyaluronidase activity after its inhibition by serum. 2. The known properties of the venom protease are found to be identical with those of Haas' "proinvasin I." It is concluded that the protease of the venom offers adequate explanation for the effects previously attributed to "proinvasin I." 3. Proteolytic activity is found in hyaluronidase preparations of bovine origin and is considered to be responsible for the reversal of inhibition of hyaluronidase by serum.