1. The cells of the stratum corneum are rough, jagged, and contain myriad niches in which bacteria dwell. The complex structure of the stratum corneum limits complete access of any chemical; an antiseptic agent must have contact to kill bacteria. 2. Shaving hair on the skin, long considered essential prior to surgery, has been shown to sabotage the effectiveness of the preoperative skin preparation. 3. Experimental evidence over a long period has documented that no other agent can achieve as rapid and large a reduction in skin flora as alcohol. 4. The preoperative hand scrub calls not only for removal of dirt, grease, and pathogens from the surface of the hands, but also a maximum reduction of the resident flora.