Excluding debtors (who are non-criminal prisoners), a local prison is one containing persons charged with an offence awaiting trial, or convicted and serving a sentence of imprison ment of less than two years. A convict prison contains con victed prisoners sentenced to three or more years' penal servitude. All prisoners sentenced to penal servitude have been while awaiting trial, or are for a short time after sentence, detained in a local prison, and thus come within the cognisance of the medical officer there.