ABSTRACT
For over two billion years, through the apparent fancy of her endless differentiations and metamorphosis, the Cell, as regards its basic physiological mechanisms, has remained one and the same. Food safety analysts, for example, might test foods for contaminating bacteria. Plant scientists might study bacteria that affect the properties of soils. Ecologists might study the roles of bacteria in nutrient cycling throughout an ecosystem. Mammalian cell culturists, therefore, learn to be extremely vigilant to avoid contamination. The invention of the light microscope was one of the most important technological advances in the history of biology. The air, surfaces of objects, skin, and breath all harbor billions of potential contaminants. Cross-contamination is another concern when working with cell culture. The hardened medium creates a solid substrate on top of which bacteria readily grow, extracting the nutrients from the medium on which they sit.
