Buckmaster's Elements of animal physiology / by John Angell.

  • Angell, John
Date:
1866
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Licence: Public Domain Mark

Credit: Buckmaster's Elements of animal physiology / by John Angell. Source: Wellcome Collection.

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    about 4 or 5 inches apart on a white background against the wall; then place yourself before the paper, and look fixedly at the paper ; close the left eye, then move gently backward, keep- ing the eye fixed on the wafers; at a certain distance the right- hand wafer becomes invisible, but reappears on going nearer to or farther from the paper ; at the point at which the right-hand wafer disappears its image falls on the puncium ccecum or optic pore of the left eye. SlGep is the fimctional repose of the cerebrum and sensory ganglia. Where injury or accident has exposed the brain to view, it has been observed to be quiet and motionless during sleep, but to pulsate and throb vigorously during dreams, and in the waking state, especially during excitement. An average of seven to eight hours’ sleep is required by those whose occupa- tions involve much mental labour or atixiety. Dreaming is caused by the partial activity of the cerebrum and sensorial ganglia during imperfect sleep. *• Somnambulism (from L., somnus, sleep; and ambulo, I walk) is a peculiar state of cerebral activity, in which the sen- sorium is in a state of repose or suspended activity. Functions of the Cerebrum (omitted from page 298).— The cerebrum is the seat of the intellect, emotions, and the will. When it is removed from the lower animals they lose their memory and power of volition. When it is very much below the ordinary size, the individual is deficient in mental power, and in most cases idiotic. When it becomes softened or hiflamed, idiotcy or delirium sets in. The intelligence and the reaso?iing faculties are affected by poisonous or intoxicating agents, which act upon the cerebnim. (See pages 15, 292, 294.) Venous Pulse.—The orifice of the superior vejta cava is not supplied with a valve, the weight of the descending column of the blood acting as a substitute. Each time, however, the right auricle contracts, a backward pixlsation, which is visible in the jugidar veins of the neck, is produced, which is termed the venotts ' pulse. The Respiratory Venous Pulse (a fulness of the vessels of the neck distinct from that just described) is caused by the pressure on the vessels during the contractmi of the chest in the act of expiration. j
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