We generalize the factorization of the classical Lipschitz quaternions
to the Lipschitz type quaternions associated with the quaternary
quadratic form x2 + 2y2 + 2z2 + 4w2. We are able to prove a
unique factorization theorem under a suitable model for the Lipschitz
type quaternions in question. As a consequence, we obtain a simple and
conceptual proof for the number of representations of a positive integer
in terms of the above quadratic form, which was first historically stated
by Liouville.