Abstract
Summary Limb buds which had been allowed to take up radioactive sulfate were extracted and fractionated in the presence of crude non-radioactive polysaccharide-protein complex from 12-day chick embryos. The radioactive material was not soluble and did not become soluble after incubation for 18 hours at 37° in sodium hydroxide but did become readily soluble after digestion with papain. After treatment with sodium hydroxide and papain, the radioactive material was excluded by Sephaclex G-50, but. after treatment with hyaluronidase, the material was held up on the same column. Fractionation of the calcium salts of the radioactive material suggested the presence of chondroitin sulfates A, C, and a small amount of B.