In Rappaccini's Daughter, once Giovanni discovers that he is also poisonous, he is very hard on Beatrice. What examples within the text indicate...

Prior to coming into contact with or seeing Beatrice, Giovanni is warned by his own sense of danger while surveying the garden from his window. He sees Rappaccini taking strenuous precautions while tending his garden, and senses that a "deadlier malice" is perhaps contained therein. Later, Giovanni witnesses a lizard die seemingly as a result of coming into physical contact with Beatrice's skin, and later sees an insect meet the same fate. In these instances, Giovanni feels that his senses are deceiving him.

The professor warns Giovanni about Rappaccini early on, saying "there are certain grave objections to his professional character." Some time later, the professor is more specific in his warnings, saying "I tell thee, my poor Giovanni, that Rappaccini has a scientific interest in thee. Thou hast fallen into fearful hands! And the Signora Beatrice? What part does she act in this mystery?" This is a specific warning of the dangers of Rappaccini's scientific experimentation, and a vaguer warning about Beatrice as well.