The cups themselves are a holy grail - the no.1 symbol for the Amanita mushroom as sacrament. Waite himself wrote many volumes on this topic and is an expert on the matter - he explicitly knows these are allegories.
I assume you mean that Waite wrote books on the Holy Grail - two, in fact (the second is an extensive revision of the first). He also wrote about the Grail in his poetry and in several articles. However, it is unclear as to whether you are saying that he also wrote about drugs and specificially the Amanita muscaria. Do you have references for Waite's writings on drugs?
