One of the earliest germanium transistors was the 2N404. It became a popular transistor for use in projects after the demand for germanium transistors fell when Texas Instruments and other companies started selling silicon transistors (for more transistor history see here). I recently bought some germanium transistors labeled 2N404, but they seem to have much higher current gain than the original 2N404s. No matter, they make excellent vampire Joule Thiefs, because they will drain every last drop of blood.. er, juice from a battery. Here in a picture I show the LED still glowing red as the battery measures 0.278 volts. The silicon transistor JTs would have stopped working at a voltage somewhat under a half volt. Admittedly the LED is dim, but it´s still working!