SECTION 1. Section eight of Act Numbered Twenty-four hundred and eighty-nine, entitled "An Act authorizing special compensation, credits, and modification in the sentence of prisoners as a reward for exceptional conduct and workmanship and for other purposes" is hereby amended to read as follows:
"SEC. 8. The benefits accruing under this Act shall not be made applicable to any prisoner who has previously been convicted twice or oftener of any crime or misdemeanor : Provided, however, That recidivists and habitual delinquents who have observed excellent conduct and behavior for a period of not less than one year and who have acquired skill in any of the industrial shops of the Bureau of Prisons may receive the compensation authorized in section one of this Act.