In 1938, I produced the twenty-fifth substance in this series of lysergic acid derivatives: lysergic acid diethylamide, abbreviated LSD-25 (Lyserg-säure-diäthylamid) for laboratory usage.
[...]
The new substance, however, aroused no special interest in our pharmacologists and physicians; testing was therefore discontinued.
For the next five years, nothing more was heard of the substance LSD-25. Meanwhile, my work in the ergot field advanced further in other areas.
And yet I could not forget the relatively uninteresting LSD-25.
A peculiar presentiment-the feeling that this substance could possess properties other than those established in the first investigations-induced me, five years after the first sy
n
thesis, to produce LSD-25 once again so that a sample could be given to the pharmacological department for further tests.
[...]
In the spring of 1943, I repeated the synthesis of LSD-25. As in the first synthesis, this involved the production of only a few centigrams of the compound. In the final step of the synthesis, during the purification and crystallization of lysergic acid diethylamide in the form of a tartrate (tartaric acid salt), I was interrupted in my work by unusual sensations.
