Vatican as part of an independent investigation. Some claimed that the wounds were unexplainable and never seem to have become infected. Despite seeming to heal they would then reappear periodically. Alberto Caserta took X-rays of Pio's hands in 1954 and found no abnormality in the bone structure. Some critics accused Pio of faking the stigmata, for example by using carbolic acid to make the wounds. Maria De Vito (the cousin of the local pharmacist Valentini Vista at Foggia) testified that the young Pio bought carbolic acid and the great quantity of four grams of veratrine "without presenting any medical prescription whatsoever" and "in great secret". Veratrine is a "mixture of alkaloids", a "highly caustic product": "Veratrine is so poisonous, that only a doctor can decide whether to prescribe it", as the pharmacist Vista stated in front of witnesses. Veratrine was once used as a paralyzing muscle insecticide, primarily against lice, but was also described by pharmacists as an "external stimulant" that renders one insensitive to pain. Pio maintained that the carbolic acid was used to sterilize syringes used for medical treatments and that after being subjected to a practical joke where veratrine was mixed with snuff tobacco, causing uncontrollable sneezing after ingestion, he decided to acquire his own quantity of the substance in order to play the same joke on his confreres; the bishop of Volterra, Raffaello Rossi came to share this view, believing that "Instead of malice, what is revealed here is Padre Pio's simplicity, and his playful spirit", and that "the stigmata at issue are not a work of the devil, nor a gross deceit, a fraud, the trick of a devious and malicious person[...] his "stigmata" do not seem to me a morbid product of external suggestion." Rossi saw these stigmata as a "real fact". Transverberation In August 1918, a few weeks before reportedly receiving the stigmata, Pio described a mystical experience during which he felt being pierced and burnt spiritually and physically. According to Pio, this mystical experience began on 5 August and ended on 7 August. Padre Benedetto, his spiritual director, interpreted this phenomenon as a transverberation. Pio later clamied that this experience left a physical wound on his left side. Most witnesses who examined Pio's wounds reported that he had a wound on his left side, around three-inch long and the shape of a cross. Pio described this experience to Padre Benedetto in a