The article discusses the development and testing of a crude membrane model to study the binding energies of narcotics, finding that lipid plays an essential role in the interactions. The model's sensitivity to inert gases and its quantitative similarity to biological effects suggest further studies on its physical state changes under narcotics may be informative. The authors thank Sheldon Gottlieb and the Linde Company for their support and acknowledge funding from the National Heart Institute. In the second part, the authors describe a method to detect and measure collagenolytic activity in amphibian tissues using tissue culture. They use fibrous collagen as a substrate and measure lysis around the explant and the hydroxyproline content of degraded collagen. The study focuses on tadpoles, particularly those not undergoing active metamorphosis, to investigate the rapid removal of structural tissue elements. The method involves culturing tissue fragments on collagen gels and observing lysis and hydroxyproline release. The results show that living tissue is necessary for substrate lysis, and the extent of lysis is proportional to the size of the tissue explant. The collagenolytic activity is also compared with that of bacterial collagenase, showing a linear increase over time. The study concludes that true collagenolytic enzyme systems exist in certain animal tissues, and the experimental system may be developed into a quantitative assay for collagenolytic activity.The article discusses the development and testing of a crude membrane model to study the binding energies of narcotics, finding that lipid plays an essential role in the interactions. The model's sensitivity to inert gases and its quantitative similarity to biological effects suggest further studies on its physical state changes under narcotics may be informative. The authors thank Sheldon Gottlieb and the Linde Company for their support and acknowledge funding from the National Heart Institute. In the second part, the authors describe a method to detect and measure collagenolytic activity in amphibian tissues using tissue culture. They use fibrous collagen as a substrate and measure lysis around the explant and the hydroxyproline content of degraded collagen. The study focuses on tadpoles, particularly those not undergoing active metamorphosis, to investigate the rapid removal of structural tissue elements. The method involves culturing tissue fragments on collagen gels and observing lysis and hydroxyproline release. The results show that living tissue is necessary for substrate lysis, and the extent of lysis is proportional to the size of the tissue explant. The collagenolytic activity is also compared with that of bacterial collagenase, showing a linear increase over time. The study concludes that true collagenolytic enzyme systems exist in certain animal tissues, and the experimental system may be developed into a quantitative assay for collagenolytic activity.