  A sufficient condition for the spatial collapse in an infinite system of
interacting Bose particles is obtained on the basis of the variational
principle with the use of trial functions with the Jastrow pair correlation
factors. The instability of a hypothetical infinite system of
$\alpha$-particles with respect to the spatial collapse is shown under the
assumption of the Ali - Bodmer interaction potentials between such Bose
particles. Thus, it becomes clear why the hypothetical nuclear matter is
naturally treated with the use of at least the nucleon degrees of freedom.
