pneumatic correspondence of note

The writers Franz Kafka and Max Brod were great friends. When Kafka died, it was Brod who ignored his request to burn Kafka's life's work, and had them published instead. The two communicated often, including by pneumatic post:

An instant message of its time, Franz was to meet Max with his interesting cousin that evening. A Paraguayan in Prague, and no doubt a lively evening ahead.

Note published in the book of Franz Kafka's correspondence entitled: Letters to Friends, Family and Editors (published 1977).