To assume censorship of the mails was a new experience to our government, for it was in direct opposition to American customs and traditions and was extremely repugnant to a large and influential section of the American people. It was undertaken, indeed, only after its necessity had been urgently and repeatedly emphasized by our allies. Early in the war France had taken over the censorship of the Swiss mails, leaving to England the supervision of the mails to and from Holland and the Scandinavian countries. Little attention had been paid, however, to the Spanish, Mexican, and Central and South American mails, save when they passed through the postal barrier erected by the Allied censorship around the neutral states of Europe. The first problem that faced the American censors, therefore, was to close the channels of information leading into Germany through Spain, or out of Germany, via Spain, to the Americas, Spain being in constant communication with Berlin by a powerful system of wireless. Upon our entrance into the war it became imperative to close this gap in the news blockade which was in force against the enemy. This done, the only possible way for a German sympathizer in the western hemisphere to communicate with Germany was indirectly, through an intermediary in a neutral country, it becoming necessary for a German agent in South America, for example, to direct his communications to some confederate in Holland or Scandinavia. Such communications, which were usually disguised as innocent social or business letters, but in reality contained concealed messages in code, cipher, or invisible ink, would then be transcribed by the confederate in the neutral country and forwarded to the particular bureau of the German Government for which they were intended, either by special courier or through ordinary postal channels.