Late eighteenth-and early nineteenth-century prisons were places of unbridled misconduct, overcrowding, illicit activity, and disease. Ironically, within prisons constructed before germ theory, the push for solitary confinement was not affected by the knowledge that human contact spreads disease; rather, the purpose of constructing individual cells was to prevent the spread of moral disease from inmate to inmate. The notion that constant silence and solitude can instill virtue, although it seems draconian, was a driving force behind penal reform that inspired the construction of silent and separate prisons around the world. A prison that was both silent and separate forbade communication between inmates, or speech in general, and housed each inmate in his or her own cell. Comparison of varying silent and separate prison systems gives context to reform taking place specifically within prisons such as Sing Sing.