The stimulus for this politic disavowal, and one must be sought, since German statements always had a genesis in antecedent events--was not apparently due to continued plot exposures, which were too frequent, but could reasonably be traced to a ringing address President Wilson had previously made to Congress on December 7, 1915. The President, amid the prolonged applause of both Houses, meeting in joint session, denounced the unpatriotism of many Americans of foreign descent. He warned Congress that the gravest threats against the nation's peace and safety came from within, not from without. Without naming German-Americans, he declared that many "had poured the poison of disloyalty into the very arteries of our national life," and called for the prompt exercise of the processes of law to purge the country "of the corrupt distempers brought on by these citizens." "I am urging you," he said in solemn tones, "to do nothing less than save the honor and self-respect of the nation. Such creatures of passion, disloyalty, and anarchy must be crushed out." Three days before this denunciation, the Administration had demanded from Germany the recall of Captains Boy-Ed and Von Papen, respectively the military aid and naval attache of the German embassy. Unlike the procedure followed in requesting Dr. Dumba's recall, no reasons were given. None according to historic usage were necessary, and if reasons were given, they could not be questioned. It was sufficient that a diplomatic officer was _non persona grata_ by the fact that his withdrawal was demanded. Germany, through her embassy, showed some obduracy in acting upon a request for these officials' recall without citing the cause of complaint. There was an anxiety that neither should be recalled with the imputation resting upon them that they were concerned, say, in the so-called Huerta-Mexican plot--if one really existed--or with the conspiracies to destroy munition plants and munition ships, or, in Captain Boy-Ed's case, in the Hamburg-American line's chartered ships for provisioning of German cruisers, sailing with false manifests and clearance papers.