The person in Dr. Jekyll's cabinet has been demanding specific ingredients from the chemist, and has sent Poole (Dr. Jekyll's butler) on several errands to fetch the ingredient for him.  Every time that Poole returns with the ingredient for his master, the contents are not to his satisfaction, and Poole is sent once again to the chemist to get the drug his master so desperately needs.  The final request that Poole's master leaves him is to take another slip back to the chemist, Messrs Maw, from Dr. Jekyll politely telling him that the contents he just gave him were not as good or as pure as the same contents he had purchased in a previous year, and asks politely if Messrs Maw could please search with the utmost care for the old, pure drug that he needs.  However, at the end of Dr. Jekyll’s letter to Messrs Maw, he breaks into strong emotion and rudely demands, "For God's sake,'...`find me some of the old.'  This angers Messrs Maw upon reading the note and he refuses to assist him.  Therefore, the person in Jekyll's cabinet (Dr. Jekyll who is trapped in the persona of Mr. Hyde) has been demanding a certain drug for the past week and has been unable to attain it because 1) it is difficult to come by and 2) he insults the one chemist who can really help him, Messrs Maw, who refuses to help Dr. Jekyll further.