A Collodion Sac for Use in Animal Experimentation

Abstract

These sacs, for the introduction of bacteria, within a semi-permeable membrane, into the animal body (peritoneal cavity), represent a radical departure from those of Gates (1921) although many of his technical details have been adopted. Stainless-steel wire gauze curved as a cylinder is closed at both ends with molded carnauba wax, and a glass tube is passed through one end. Both ends of the sac and the line of approximation of the gauze are covered with alcohol-ether collodion, which is allowed to dry for several hours. The sac is dipped in the percentage of acetic-acid collodion required in the given expt., allowed to drain a specified time (the collodion that collects at the bottom on the inside is asplrated), and then plunged into filtered tap water. All of the solvent is washed out in periodic changes of the water. The rate of flow of water is measured. The sac is sterilized for about 18 hrs. in a soln. of 1 part of "B.K." (hypochlorite soln.) in 100 parts of distilled water and then washed in a large volume of sterile distilled water. The sac is filled by a Pasteur plpette and sealed with paraffin and collodion. At the completion of the in vivo expt., the sac is opened by thrusting a hot wire through the collodion and paraffin seal, and the contents are removed by a Pasteur pipette.