  We give a presentation of Schur algebras (over the rational number field) by
generators and relations, in fact a presentation which is compatible with
Serre's presentation of the universal enveloping algebra of a simple Lie
algebra. In the process we find a new basis for Schur algebras, a truncated
form of the usual PBW basis. We also locate the integral Schur algebra within
the presented algebra as the analogue of Kostant's Z-form, and show that it has
an integral basis which is a truncated version of Kostant's basis.
