Sources of Cells
Contamination of all kinds should be avoided during experimental manipulations. Tissues should be collected aseptically or should be sterilized after removal. All adult tissues are contaminated with bacteria except the embryo and other contents of the uterus, which are free from contamination. However, the embryo should be removed carefully under aseptic conditions, avoiding the possibility of contamination. The adult tissue is washed with a solution having high  concentration of antibiotic-a balanced salt solution containing 100 units of penicillin and 0.5 mg of streptomycin or neomycin permilliliter. Further handling of tissue is done under fully aseptic conditions, either in an aseptic room or through the use of laminar flow cabinet or hood.