No department, agency, or
instrumentality of the United States which
uses animals for research or experimentation
or exhibition shall purchase or otherwise
acquire any dog or cat for such purposes
from any person except an operator of an
auction sale subject to section 2142 of this
title or a person holding a valid license as a
dealer or exhibitor issued by the Secretary
pursuant to this chapter unless such person
is exempted from obtaining such license
under section 2133 of this title.