Pliny the Elder,
Natural History 7.80 (tr. Mary Beagon):
But minor peculiarities of nature take many forms and are very
common. Drusus' wife, Antonia, for example, did not spit and the
poet and one-time consul, Pomponius, never belched.
sed haec parva naturae insignia in multis
varia cognoscuntur; ut in Antonia Drusi numquam
exspuisse, in Pomponio consulari poeta non ructasse.
Cf.
Solinus 1.74 (p. 18 Mommsen):
Pomponium poetam consularem virum numquam ructuasse habetur inter
exempla: Antoniam Drusi non spuisse percelebre est.