Flaubert taught us that there is no neutral area in human communications, and no more merit in tolerating hideous and tendentious forms of pictorial arrangement than in putting up with polluted drinking water. Before Pasteur, Flaubert introduced the germ theory into social communication. (McLuhan NAEB presentation September 1959, reused in The Medium is the Message,1960)

The world of body and mind observed by Baudelaire and Bernard was not photographical at all, but a nonvisual set of relations such as the physicist, for example, had encountered by means of the new mathematics and statistics. The photograph might be said, also, to have brought to human attention the subvisual world of bacteria that caused Louis Pasteur to be driven from the medical profession by his indignant colleagues. Just as the painter Samuel Morse had unintentionally projected himself into the nonvisual world of the telegraph, so the photograph really transcends the pictorial by capturing the inner gestures and postures of both body and mind, yielding the new worlds of endocrinology and psychopathology. (Understanding Media, 1964, pp201-202)

The utmost purity of mind is no defense against bacteria, though the confreres of Louis Pasteur tossed him out of the medical profession for his base allegations about the invisible operation of bacteria. To resist TV, therefore, one must acquire the antidote of related media like print. (Understanding Media, 1964, p329)

TV Guide for June 8-14, 1968, has a painting by Dali on the cover. Two thumbs exhibit two TV screens as thumbnails. That is pure poetry, acute new perception. Dali immediately presents the fact that TV is a tactile mode of perception. Touch is the space of the interval, not of visual connection. I have been trying to elucidate this fact for years. In vain. The somnambulist knows better. Can’t he see TV with his eyes? How could it be tactile? Pasteur was thrown out of the medical profession because he insisted that doctors wash their hands before surgery. They knew better. They could see their hands were clean. The effects of new media on our sensory lives are similar to the effects of new poetry. They change not our thoughts but the structure of our world. (Foreword to The Interior Landscape, 1969)