The standard equations of radioactive transformation are generalized to include the case where radioactive nuclei are subject to transformation by neutron absorption in addition to spontaneous decay. Opportunity is taken to derive the equations by a simple method which avoids recourse to the formal methods of solving differential equations. A method is pointed out whereby one may write simply by inspection of the equation for the activity of a species which is descended from an ancestral species through a chain of any combination of decays and neutron absorptions. Some problems are solved as illustration.