Abstract 1. 1. A combination of ammonium sulfate precipitation, dialysis, and freezing and thawing is effective in the preparation of various fractions of ragweed pollen, and in the separation of the pigmented portions. 2. 2. A purified globulin has been obtained which appears to react specifically with a reagin peculiar to itself. 3. 3. Protein crystals which are highly active in direct skin tests, in neutralizing capacity, and against rabbit vs. ragweed antiserum have been obtained.