It is a common saying among nurses, that there is a difference in the size and form of the pregnant woman, according to the sex she carries. This may well be doubted. Neither is it true that one sex is more active in its 'movements' than the other. It is quite possible, however, for a wife to know the sex of the fœtus, if she can tell about what time in her month conception took place. If it occurred directly after a monthly sickness, the child is a girl; if directly before, it is a boy. When a woman is 'out' in her reckoning, and goes beyond the period of her expected confinement, it will ordinarily turn out to be a boy. The skilful doctor can, in the later months of pregnancy, settle the question of sex in some cases. The beats of the fœtal heart are more frequent in females than in males. The average frequency of pulsations of twenty-eight female fœtuses has been found to be one hundred and forty-four in the minute, the lowest figure being one hundred and thirty-eight; of twenty-two male fœtuses, one hundred and twenty, the lowest figure being one hundred and twelve. Therefore, when the pulsations of the heart of the child in the womb are counted,--as can easily be done by a practised medical ear during the last months of pregnancy,--and are found to be over one hundred and thirty in a minute, it is a daughter; if under one hundred and thirty, a son. In this manner, the sex of an unborn child can be predicted with tolerable accuracy, excepting only when illness of the fœtus has deranged the action of its heart. ARE THERE TWINS PRESENT? Certain signs lead to the suspicion of twins, such as being unusually large, and the fact that the increase in size has been more than ordinarily rapid. Sometimes also the abdomen is divided into two distinct portions by a perpendicular fissure. In other cases the movements of a child can be felt on each side at the same time. And in twin pregnancies the morning sickness is apt to be more distressing, and all the other discomforts incident to this condition increased. But these signs and symptoms, when present in any given case, are not conclusive, for they may be noticed when there is only one child. The doctor has one characteristic and infallible sign by which he can ascertain whether the woman be pregnant with twins. It is furnished to him again by the art of listening,--or auscultation, as it is technically called,--the same that, as we have already seen, may enable him to determine the sex of the child. When the beatings of two fœtal hearts are heard on opposite portions of the abdomen, the nature of the pregnancy is apparent. LENGTH OF PREGNANCY.