“ Where the questions presented by an application for an interlocutory injunction are grave, and the injury to the moving party will be certain and irreparable, if the application be denied and the final decree be in his favor, while if the injunction be granted the injury to the opposing party, even if the final decree be in his favor, will be inconsiderable, or may be adequately indemnified by a bond, the injunction usually will be granted. ”

“ The statute provides for the enforced payment of the tax quarterly in each year. If the tax be paid during the pendency of the suit, and the statute be adjudged invalid by the final decree, the plaintiff will be remediless. The laws of the state afford no remedy whereby restitution of the money so paid may be enforced, even where the payment is under both protest and compulsion. ”

“ The parties are citizens of different states and the matter in controversy exceeds in value the jurisdictional requirement. On bringing the suit, the plaintiff applied for an interlocutory injunction restraining the enforcement against it of the amendatory act pending the decree on final hearing ”