Pervitin was supposedly a powder form drug that "enabled scouts (in finland during finnish war) to walk and fight continuously for many days and nights without any sleep nor with much food". The rumour also tells it was manufactured in the nazi germany and it caused hallucinations if the use was prolonged over a long period (chemical sleep deprivation). Some claim that it is just a rumour, and not much of documents telling about it exist anymore.
Some sources indicate that pervitin was not a powder form drug, but it was pressed as a tablet. The nazi-german stimulant was called "Pervitin", and it was classified (in Finland) as hormonal-product (sic!) during the wartime. Effect was supposedly similar to adrenaline and noradrenaline even that pervitin was completely synthetic chemical. It belongs to same group with ephedrine (which is found from the plants, even from the banana skins (perhaps this is the reason why such urban-legend about banana-skin drugs exists?)) and benzedrine. Benzedrine is also fully synthetic (1-phenyl-2-aminopropane-sulphate) aka. "speed" in the streets and "amphetamine" in the medical world.
So Pervitin was a brand-name for a stimulant that was designed to enchance soldiers performance, without having bad side effects of adrenalines (it is very hard to shoot well if your heart is going like pneumatic drill).
The chemical name for pervitin is methamphetamine and the effect was the same that can be obtained from the street meth. Street speed (in USA) is usually meth as it is much easier to produce in clandestine labs than "real" amphetamine. Street speed can also contain other unwanted sideproducts, such as strychnine. Strychnine can potentiate the effects of speed in CNS even in very small doses. Strychnine was even used as its own to enchance endurance in sports some 100 years ago.
The reason why nazi pervitin was originally more likely a product that contains methamphetamine than a dextroamphetamine is the same as for clandestine labs: It is MUCH easier to produce. It can be quite easily produced with widely available chemicals (during wartime) from ephedrine or pseudoephedrine and it is supposedly more potent than amphetamine. And furthermore, it is not easy task to sort out levo- and dextro- amphetamines from each other (especially during hard war efforts).
"Pete", "Höökipulveri", (online) http://www.guns.connect.fi/gow/kysvast3.html,ref. 20.6.2002.