[BrendaAnnD]

Germanium transistors almost uniformly suffer from what is called "whisker disease". Crystalline 'whiskers' grow out from the active element, and eventually will contact the outside metal cover of the transistor. This is a problem no matter what, but if whiskers from more than one point reach the cover, it shorts the transistor out. Some brands of transistor have lasted better than others, but so far reports of all brands doing this have been published.