“ It is true the Secretary recites that legislation has been passed by the state of Tennessee to enforce the quarantine line, but he does not limit the order to interstate commerce coming from the south of the line, and, as we have said, the order in terms covers it. We do not say that the state line might not be adopted in a proper case, in the exercise of Federal authority, if limited in its effect to interstate commerce coming from below the line, but that is not the present order, and we must deal with it as we find it. ”

“ We are not able to reject a part which is unconstitutional and retain the remainder, because it is not possible to separate that which is unconstitutional, if there be any such, from that which is not. ”

“ The railroad company, by the proceedings and judgment in this case, was denied the alleged Federal rights and immunities specially set up in the proceedings, in the enforcement of a statute and departmental orders averred to be beyond the constitutional power of Congress and the authority of the Secretary of Agriculture, and in the rendition of a judgment for damages in an action under the statute and order, in opposition to the insistence of the defendant that, even if constitutional, the statute did not confer such power or authorize a judgment for damages. ”