A membrane model was developed to study a phenomenon, with binding energies matching in vivo experiments when lipid was included. The model's behavior does not clarify whether interactions occur between lipid and narcotic or between water and narcotic. However, data suggest lipid plays a crucial role, even in non-surface active substances. The model's sensitivity to inert gases and similarity to biological effects indicate further studies on physical state changes under narcotics may be informative. The authors thank Sheldon Gottlieb and Linde Company officials for discussions and gas supplies. This work was supported by a grant from the National Heart Institute. The study presents a tissue culture assay for collagenolytic activity in amphibian tissues. Collagenolytic activity was detected by lysis of fibrous gels and hydroxyproline content. Tadpole tissues, particularly skin, gut, and gill, showed significant collagenolytic activity, while other tissues like muscle and heart did not. The activity was temperature-dependent, with higher activity at 37°C. The activity was not present in dead tissue or in extracts from tadpole tissues using standard assays. The results suggest that collagenolytic enzymes exist in certain animal tissues, capable of degrading collagen to dialyzable fragments. The study also observed collagenolysis in post-partum myometrium, chick embryo skin, and newborn mouse and rat bone. The findings indicate that collagenolytic activity is not limited to specific tissues and may be influenced by factors such as temperature and the presence of living tissue. The study highlights the importance of collagenolytic activity in tissue remodeling during amphibian metamorphosis. The results suggest that collagenolytic enzymes may be stored within cells and released upon demand, or synthesized de novo. The study also notes that collagen may be removed through structural alterations rather than specific enzymatic activity. The findings contribute to the understanding of collagenolytic activity in animal tissues and its role in physiological processes.A membrane model was developed to study a phenomenon, with binding energies matching in vivo experiments when lipid was included. The model's behavior does not clarify whether interactions occur between lipid and narcotic or between water and narcotic. However, data suggest lipid plays a crucial role, even in non-surface active substances. The model's sensitivity to inert gases and similarity to biological effects indicate further studies on physical state changes under narcotics may be informative. The authors thank Sheldon Gottlieb and Linde Company officials for discussions and gas supplies. This work was supported by a grant from the National Heart Institute. The study presents a tissue culture assay for collagenolytic activity in amphibian tissues. Collagenolytic activity was detected by lysis of fibrous gels and hydroxyproline content. Tadpole tissues, particularly skin, gut, and gill, showed significant collagenolytic activity, while other tissues like muscle and heart did not. The activity was temperature-dependent, with higher activity at 37°C. The activity was not present in dead tissue or in extracts from tadpole tissues using standard assays. The results suggest that collagenolytic enzymes exist in certain animal tissues, capable of degrading collagen to dialyzable fragments. The study also observed collagenolysis in post-partum myometrium, chick embryo skin, and newborn mouse and rat bone. The findings indicate that collagenolytic activity is not limited to specific tissues and may be influenced by factors such as temperature and the presence of living tissue. The study highlights the importance of collagenolytic activity in tissue remodeling during amphibian metamorphosis. The results suggest that collagenolytic enzymes may be stored within cells and released upon demand, or synthesized de novo. The study also notes that collagen may be removed through structural alterations rather than specific enzymatic activity. The findings contribute to the understanding of collagenolytic activity in animal tissues and its role in physiological processes.