 (i) The first type of movement is based on the reaction to objects that are present. In this case, Pereira formulated an explanation that embraced a pioneering theory of reflex reaction which involved both peripherical stimuli and a central organ. The process as it was described by him consisted of four phases. It starts with the object that stimulates the sensory organs. This stimulation leads to reactions in the sensory organs which cause certain mechanical alteration called by Pereira species. The sense of touch occupies a special category into this explanation model, since in this sense the process is not activated by means of mechanical alterations caused by distant object, but by direct physical contact between the object and the organism, without the intervention of those species. The second phase consists of the transmission of the alteration in the sensory organ to the brain. This transmission of the species to the brain takes place without any resistance, so that it spreads along the nerves at an enormous speed. The third phase is located in the brain and consists of the activation of the areas where the motor nerves originate (Pereira considered the connections corresponding to each sensorial modality to have a specific location in the brain). And finally, the fourth and last phase consists of the activation of the nerves which gives way to contraction and distention of the muscles that generates the movement of the different parts of the animal (AM: I.243–245).