It's a matter of fact that currently we think of drugs or pills as a theraputic tools as well as a way to enjoy some kind of activities like parties. However, we don't usually think how scientists got to know about this kind of substances and their effects for the human mind. The usual way to do research in this kind of stuffs is make animals as rats to try this kind of pills and see the effects produced by them in the animal behaviour. Scientists suppose this kind of modifications can be supposed to be similar to the modifications these pharmacs can produce in human brain, maind, behaviour and organism all together. Nevertheless, sometimes this method and the results produced by it are neither reliable nor enough.
Between 1930-1940, Alfred Hofmann worked in Sandoz Pharmaceutics studying the ergot (a fungus that grows in the cereals). He didn't find any interesting property when he tried this fungus with different kind of animals. However it was, Hofmann decided to get back to study with one of the compuunds extracted out of the ergot. Instead of trying with animals anymore, he took himself the compound: "An uninterrupted series of phantastic images, extraordinary forms with an intense and kaleidoscopic range of colors" (Hofmann 1981). He suspected he didn't take enough, so he tried again. After some experiencies with this compound, he discovered that just with a little of this substance he felt incredible disabling changes in brain functions, as visual phenomena, or the feeling of being an integrated ego (he felt he was "lazy, loose").
We can discuss if he was responsible or sensible, but the important thing here is that we couldn't know anything about LSD today if Hofmann never had tried the compund he almost ruled out because it had no effect in animals. It was his phenomenological experience the crucialpoint to start to do research about this compound seriously and, later, to know its mechanisms to understand its effects in the mind. Phenomenology, as well as neuroscience and chemistry, was an essential factor for the discovery and research on this compound.
Hofmann, Albert (1981): LSD, My Problem Child. McGraw-Hill. ISBN 0-07-029325-2