Which characteristic is essential for a good fixative?

A good fixative should penetrate cells quickly because this characteristic ensures that cellular structures are preserved effectively and in a timely manner. Quick penetration allows the fixative to stabilize proteins and other intracellular components before any degradation or autolysis occurs. If the fixative takes too long to penetrate, it may lead to inadequate preservation of the cellular morphology, which is crucial for accurate diagnosis and analysis in laboratory settings.

In addition to rapid penetration, a good fixative is generally expected to maintain the structural integrity of the cells and tissues while also allowing for subsequent staining procedures. Though other characteristics, such as being compatible with water-based stains, are important, the primary focus on quick penetration emphasizes the need for immediate preservation of cellular details, which is vital for effective microscopic examination.