How we cite our quotes: (Chapter.Section.Paragraph)
Quote #1
Otto had in fact told me that during his short stay with Irma's family he had been called in to a neighbouring hotel to give an injection to someone who had suddenly felt unwell. These injections reminded me once more of my unfortunate friend who had poisoned himself with cocaine. I had advised him to use the drug internally [i.e., orally] only, while morphia was being withdrawn; but he had at once given himself cocaine injections. (P.1.23)
The medical use of cocaine was very new in the Europe of Freud's day, and Freud himself had done some of the exploratory research that led to its use as a painkiller. But with so little known about the drug, tragedies were bound to happen. The friend Freud's talking about is Ernst Fleischl von Marxow. As Alexander Grinstein notes in Sigmund Freud's Dreams, Fleischl was Freud's senior colleague at the Physiological Institute where he trained—a young man "whom Freud took as a model and almost worshipped" (source).
Quote #2
I began to guess why the formula for trimethylamin had been so prominent in the dream. So many important subjects converged upon that one word. Trimethylamin was an allusion not only to the immensely powerful factor of sexuality, but also to a person whose agreement I recalled with satisfaction whenever I felt isolated in my opinions. Surely this friend who played so large a part in my life must appear again elsewhere in these trains of thought. (2.1.40)
The unnamed friend Freud mentions here is Wilhelm Fliess. James Strachey notes that Fliess "exercised a great influence on Freud during the years immediately preceding the publication of this book," and "figures frequently, though as a rule anonymously, in its pages" (source).
Quote #3
On the one hand we see the group of ideas attached to my friend Otto, who did not understand me, who sided against me, and who made me a present of liqueur with an aroma of amyl. On the other hand we see—linked to the former group by its very contrast—the group of ideas attached to my friend in Berlin, who did understand me, who would take my side, and to whom I owed so much valuable information, dealing, amongst other things, with the chemistry of the sexual process. (6.2.44)
Here again, Freud's "friend in Berlin" is Wilhelm Fliess. Fliess is mentioned throughout The Interpretation of Dreams as a trusted friend and adviser, and he often appears in Freud's dreams. Sometimes those appearances are explicit, and sometimes his presence is felt in obscure ways that only become clear when Freud gets on with his interpretations.