The conditions upon which congestive dysmenorrhoea depends are various, and may be either general or local or both combined. Plethora is rare in females, and local congestions are much more frequently dependent upon anæmia, the abnormal condition of the blood favoring them {196} directly and also indirectly by its effect on the nervous system. In past times gout and rheumatism were considered to act frequently as the cause of dysmenorrhoea. They have almost disappeared from view since the era of direct examination began. Malaria, however, as a possible cause or a powerful factor should never be overlooked in regions where it prevails. The sexual instinct plays an important rôle; enforced abstinence, especially when suddenly brought about, and excess, being alike effective etiological factors. Young widows and prostitutes are both subject to this form of disease. The local causes are numerous. Pelvic inflammations, as cellulitis or pelvic peritonitis, give rise to the disease. Affections of the uterus are frequent causes; displacements, as retroversion or prolapsus; and inflammation, either parenchymatous or of the endometrium. Quite a moderate grade of inflammation, as found during the interval, may, under the increased congestion of menstruation, become extreme. Many cases doubtless depend upon an ovarian influence even when no affection of these organs can be made out. Scanzoni hazards the theory that the maturation of Graäfian vesicles lying deeper than usual in the stroma of the ovary is one cause of this form of dysmenorrhoea. In neuralgic dysmenorrhoea the neurotic element preponderates. The nerves play a part corresponding to that of the vessels in the congestive form. In some cases of this class no organic lesions can be discovered, and they are then termed idiopathic.