It was urged by the appellants that prohibitory measures must be permissible, for otherwise lunatics, infants and bankrupts could without restraint embark upon inter-State trade, and diseased cattle or noxious drugs could freely be taken across State frontiers. Their Lordships must therefore add, what, but for this argument so strenuously urged, they would have thought it unnecessary to add, that regulation of trade may clearly take the form of denying certain activities to persons by age or circumstances unfit to perform them or of excluding from passage across the frontier of a State creatures or things calculated to injure its citizens.
No doubt a statute that imposes reasonable restrictions in the interest of public health may be justified as a permissible regulation of interstate trade which does not infringe s. 92, and such reasonable regulation may in appropriate cases extend to the absolute prohibition of the trade in or movement into the State of dangerous goods or diseased persons, plants or animals. However it is unnecessary to discuss that question in the present case. It is impossible to agree that the prohibition of the movement of cockatoos from New South Wales to Queensland is reasonably necessary either in the interests of the health of the community or of the preservation of cockatoos. As the stated case reveals, wild cockatoos, which are to be found along the whole of the east coast of Australia and in Papua New Guinea, are continually flying across the border between New South Wales and Queensland. The number of cockatoos in commercial trade is miniscule (to use the words of the stated case) in comparison with the number of wild cockatoos. No material was placed before the Court to suggest that the species is, or is likely to be, endangered by that trade. The argument now submitted for the defendants is similar to that advanced and rejected in Fergusson v Stevenson [9] .
1. (1952) 85 C.L.R. 488, at p. 521.
2. (1949) 79 C.L.R. 497, at p. 641; [1950] A.C. 235, at pp. 311-312.
3. (1951) 84 C.L.R. 421.