nicholls emphasised that the stamp duty applied to d'emden personally, as a private citizen: that while d'emden "earns his salary as an officer, [he] receives and enjoys it as a private citizen", and that the legislation did not infringe the federal parliament's exclusive powers over the postmaster-general's department since "in giving the receipt, [d'emden] is not serving the commonwealth, but only dealing with it." nicholls also conceded that if the stamp duty was levied only on agents of the federal government then it would be unconstitutional, but stressed that it was a general tax applying to all persons in tasmania.