Opinion of the Court. Mr. Solicitor General for the plaintiffs in error. Mr. Monroe Salisbury in person for the defendant in error Salisbury. No appearance for defendant in error Piatt. MR. JUSTICE HARLAN delivered the opinion of the court. This action was instituted by the United States to recover from the defendants in error certain moneys claimed to have been paid to them for services in carrying the mail, in excess of the amount to which they were legally entitled. The first count alleges in substance that on March 15, 1878, the defendant Piatt contracted in writing with the United States, through the Postmaster General, to carry the mail three times a week for four years from July 1, 1878, for a consideration of $16,500 per annum, on the route then known as No. 36,107, between Bozeman, Montana, by way of Shields River, Crow Agency, Stillwater, Head of Navigation, Pompey's Pillar, Fort Peace, and Big Horn City, to Tongue River and back. By power of attorney, dated August 15, 1878, Piatt authorized the defendant Salisbury to collect from the Auditor of the Treasury for the Post Office Department all pay to become due for carrying the mails upon that route; and subsequently, on December 13, 1878, with the permission of the Post Office Department, he sublet his contract to Salisbury. Piatt entered upon and continued the performance of this service from July 1, 1878, until December 13, 1878, from which date the service was performed by Salisbury. For the purpose of expediting the service, the Post Office Department, by order dated December 5, 1878, on agreement with Piatt shortened the schedule of departures and arrivals on the above route after December 16, 1878, by reducing the time from 132 hours to 72 hours in summer and 96 hours in winter, allowing therefor additional compensation of $16,500 per annum, in supposed accordance with the provisions of section 3961 of the Revised Statutes of the United States. A Opinion of the Court. similar order was made January 17, 1879, allowing an additional annual sum of $3542.92 from January 25, 1879, for an increased distance on the route of 35 miles, such allowance being computed pro rata upon the basis of the compensation previously allowed. A further order dated July 15, 1879, increased the service to seven trips a week from August 1, 1879, for which the additional sum of $48,723.89 per annum was allowed upon the same basis of compensation. Both Piatt and Salisbury consented to the conditions of these orders. Piatt procured the issuing of the above orders amending the original contract. They were issued solely upon the basis of certain representations made in his sworn statement dated August 16, 1878, to the effect that to carry the mail upon said route three times a week, on a schedule of 132 hours, required 26 men and 90 horses, while the proposed expedited schedule of 72 hours in summer and 96 hours in winter would require 48 men and 200 horses. This statement was wholly false and fraudulent in that it alleged an increase of 22 men and 110 horses necessary to perform the expedited schedule, whereas in fact neither Piatt nor Salisbury ever required or used in performing the mail service, three times a week or seven times a week, more than 34 men and 100 horses, being 14 men and 100 horses less than Piatt alleged in his sworn statement were necessary for performing said expedited service three times a week. By means of such fraudulent representations by Piatt, and by means of false vouchers presented to the Post Office Department, Piatt and Salisbury received from the plaintiff a larger sum of money than they were lawfully entitled to receive. The sum so received by them during the period of their service, by means of such false statements and fraudulent vouchers, was $261,016.50, being $99,556.20 in excess of the amount that could, after certain reductions and remissions, be lawfully paid to them. The false statements above referred to were designed to mislead and did mislead the Post Office Department of the United States, and the defendants were entitled to receive from the United States for such service the sum of $148,438.23 and no more. Payment of such excess having been demanded and refused, Opinion of the Court. judgment was asked against the defendants for $99,556.20, with interest from August 21, 1882, and costs of suit. The second count is the common law count for money had and received. The third count sets forth the same facts as are embodied in the first count, and alleges that plaintiff's officers were induced to pay the $99,556.20 in mistake of fact, and that that sum was received by defendants contrary to section 3961 of the Revised Statutes of the United States. The payments referred to are set out in full in an exhibit showing the amounts defendants were lawfully entitled to receive on the basis of the actual increase of stock and carriers consequent upon the reduction in running time as before mentioned. Piatt was not served with process, nor did he appear or plead. Service of process was had upon Salisbury, who appeared and demurred both generally and specially to the complaint. The court below sustained the demurrer and dismissed the complaint as to both defendants. Each defendant is cited in the writ of error upon which this action is before us, and service acknowledged by the attorney of both. The plaintiff in error has assigned the following errors: 1. That the Circuit Court erred in sustaining Salisbury's demurrer to the complaint. 2. That judgment was wrongly given in favor of both defendants, Piatt not having appeared or pleaded. By section 3961 of the Revised Statutes of the United States it is provided that "no extra allowance shall be made for any increase of expedition in carrying the mail unless thereby the employment of additional stock and carriers is made necessary, and in such case the additional compensation shall bear no greater proportion to the additional stock and carriers necessarily employed than the compensation in the original contract bears to the stock and carriers necessarily employed in its execution." It is contended that as the statement of the contractor in every case merely stated the number of men and horses required to perform the service on the contract time, and also Opinion of the Court. how many men and horses, in his opinion, it would require to perform the service on the proposed expedited schedule, and as it merely alleged that the subcontractor or person who performed the service did not use the men and horses stated to be necessary, the complaint is insufficient to maintain this action, for the reason that section 3961 of the Revised Statutes, under which the action is brought, provides nothing as to men and horses, but does provide that the allowance for expedition shall be based upon the additional stock and carriers made necessary by the expedited schedule. And, it is said, "there is not a word in the complaint that charges that the defendants did not employ additional stock and carriers on the expedited schedule in exact proportion to the expedition allowance." It is also said that the words "stock and carriers" in section 3961 are not synonymous with the words "men and horses;" that the word "stock" does not mean simply live stock, nor does the word "carriers" mean either horses or men, but rather includes all the equipment of the route, whether horses, wagons, harness, stage stations, fuel, food, stables, in fact everything needed to carry on the service, such being the popular sense in which these words are used. There is nothing of substance in these contentions. Whatever may be comprehended by the term "stock and carriers" in section 3961, it certainly includes within it "men and horses;" and as the Postmaster General could allow an increased compensation only in conformity with that statute, it must be assumed that he did so upon the basis of the sworn statement alleging an increase of "men and horses" necessary for the performance of the expedited schedule. The defendants in error are bound by this sworn statement, and as the increased compensation was ordered only upon the assumption of the truth of its allegations and in conformity with the statute, and as they agreed to the amendment of the original contract in this regard, they are estopped from asserting that this sworn statement was not intended to bring the contract within the statute. If the term "stock and carriers" does not include "men and . Opinion of the Court. horses," then the Postmaster General had no right to make the increased allowance mentioned, and if this be true, such additional allowances exceeded the "sum which, according to law, might rightfully have been allowed therefor," and by the provisions of section 4057 of the Revised Statutes the Postmaster General "shall cause suit to be brought to recover such wrong payment, or excess, with interest thereon." But, as by the provisions of section 3961, "no extra allowance shall be made for any increase of expedition in carrying the mail unless thereby the employmen of additional stock and carriers is made necessary," and as the Postmaster General, upon the defendant Piatt's sworn statement that certain increases of men and horses were necessary to perform the service upon the proposed expedited schedule, made the said allowance of increased compensation, the conclusion must be that the plaintiff made and the defendants accepted the amended contract, with the understanding that it was within the provisions of the statute. The defendants in error further contend that the increased allowances in question were not made by the Postmaster General solely upon the basis of the sworn statement designating the additional number of men and horses necessary to perform the service upon the proposed expedited schedule, but that it was merely for the information of the Postmaster General in making the new schedules. But whether it be true or not that he acted solely upon such representations, it is sufficient that they constituted a substantial part of the information from which he made the new schedules allowing increased compensation. The complaint, however, alleges that the Postmaster General did allow the increased compensation solely upon the basis of these false representations. The allegations of the complaint must be taken to be true for the purposes of this demurrer. The question is whether the facts as stated, if true, constitute a sufficient cause of action. We think they do. The third count alleges that the excessive payments in question were made by the plaintiff in mistake of fact. We do not doubt the plaintiff's right to recover the amount of |