CHAP. VI. WEEPING. 157 then follows every Lad crying-fit,, until the hahit is checked with advancing years. On the cause of the contraction of the muscles round the eyes during screaming. — -We have seen that infants and young children, whilst screaming, invariably close their eyes firmly,, "by the contraction of the surrounding muscles, so that the skin becomes wrinkled all around. With older children, and even with adults, whenever there is violent and unrestrained crying, a tendency to the contraction of these same muscles may be observed; though this is often checked in order not to interfere with vision. Sir C. Bell explains12 this action in the following manner: — "During every violent act of expiration, whether in hearty laughter, weeping, coughing, or sneez- ing, the eyeball is firmly compressed by the fibres of the orbicularis; and this is a provision for supporting and defending the vascular system of the interior of the eye from a retrograde impulse communicated to the blood in the veins at that time. When we contract the chest and expel the air, there is a retardation of the blood in the veins of the neck and head; and in the more power- ful acts of expulsion, the blood not only distends the vessels, but is even regurgitated into the minute branches. Were the eye not properly compressed at that time, and a resistance given to the shock, irreparable injury might be inflicted on the delicate textures of the interior of the eye." He further adds, " If we separate the eyelids of a child to examine the eye, while it cries and struggles with passion, by taking off the natural support to the vascular system of the eye, and means of 12 "The Anatomy of Expression,' 1844, p. 106. See also his paper in the ' Philosophical Transactions,' 1822, p. 284, ibid. 1823, pp. 166 and 289. Also * The Nervous System of the Human Body,' 3rd edit. 1836, p. 175.