How we cite our quotes: (Chapter.Section.Paragraph)
Quote #1
He had at that time confided some ideas to me on the subject of the chemistry of the sexual processes, and had mentioned among other things that he believed that one of the products of sexual metabolism was trimethylamin. Thus this substance led me to sexuality, the factor to which I attributed to greatest importance in the origin of the nervous disorders which it was my aim to cure. (2.1.39)
As he analyzes his Dream of Irma's Injection, Freud interprets the appearance of "trimethylamin" in the dream as an obscure allusion to the theme of sexuality. As he notes in this passage, Freud believed that unconscious sexual instincts were the cause of the nervous disorders he treated in his patients.
Quote #2
Though we think highly of the happiness of childhood because it is still innocent of sexual desires, we should not forget what a fruitful source of disappointment and renunciation, and consequently what a stimulus to dreaming, may be provided by the other of the two great vital instincts. (3.1.17)
Freud is playing to his conservative readers here when he speaks of childhood as being "innocent of sexual desires." In fact, his theory of dreaming is based largely on the idea that children do have sexual wishes and desires, which are later repressed and inaccessible to the waking minds of their adult selves. In fact, even here Freud adds a footnote to say that "sexual instinctual forces, in infantile form, play a large enough part, and one that has been too long overlooked, in the psychical activity of children" (3.1.17).
Quote #3
Identification is most frequently used in hysteria to express a common sexual element. A hysterical woman identifies herself in her symptoms most readily—though not exclusively—with people with whom she has had sexual relations or with people who have had sexual relations with the same people as herself. […] In hysterical phantasies, just as in dreams, it is enough for purposes of identification that the subject should have thoughts of sexual relations without their having necessarily taken place in reality. (4.1.36)
Freud's work on hysteria and other neuroses in women has inspired decades of feminist analysis, and his treatment of women's sexuality has often been critiqued. Jeffrey Moussaieff Masson's The Assault on Truth: Freud's Suppression of the Seduction Theory is one good place to start dipping your toes into the controversies that Freud's theories provoked.