Nuclear dissociation cross sections for halo nuclei have been assumed by va
rious authors to have a A(1/3) dependence on the target mass. These cross s
ections have also been considered to be a sum of the nuclear and Coulomb co
mponents. Explicit calculations of the break-up of C-19 induced by various
targets show that both of the above assumptions become invalid for halo nuc
lei. (C) 2001 Published by Elsevier Science B.V.