Two results are proved concerning the equations of a class of nonlinear compartmental systems. For the time-invariant case it is proved that every bounded solution approaches a limit at an exponential rate as

(which, for example, rules out the possibility that limit cycles can occur). For the case in which there are cyclic time variations with period

, it is shown (for a more general class of equations than has been considered previously) that the equations have a globally stable

-periodic solution.