In the field of animal physiology, the talented Russian researcher Nikolai Pavlovich Betsa took an active part in scientific work. His scientific research was related to the processes of formation and distribution of nerve cells in the spinal cord and medulla oblongata of adult and developing animals. Betza was one of the first to observe the development of nerve fibers and cells in the postnatal period of ontogenesis. At the beginning of his scientific career in ophthalmology, Betza became convinced of the role of the ciliary body in the process of accommodation of the eye. He discovered an autonomous center in the ciliary body, which controls the position of the cilia when the shape of the eyeball changes as a result of the accommodative reflex. After analyzing the work, Onni and his colleagues discovered not only a change in the position of the cilia under the influence of the ciliary muscle, but also a change in their shape, length and concentration. Betza believed that the movement of cilia associated with vision is carried out due to this autonomous part of the retina - the ciliary cyclops, which act synergistically. He developed the myelination of nerve fibers in the retina, reaching significant completeness. Based on the study of the nerves of the eyelids and the internal muscles of the eyes, it was concluded that nerve impulses can be transmitted along several groups of fibers without deteriorating the speed of transmission of nerve impulses. He described in general form the structure of the axonal fascicles along with the dendrites of the nerve cells of the eye. Betsa