There is, perhaps, no one circumstance which is found to exert such a prejudicial influence on the course of a natural labour, in so many different ways, as deranged and constipated bowels. Where the contents are of an unhealthy character, the irritation which they produce in the intestinal canal is quickly transmitted to the uterus, and tends not a little to pervert and derange the due and healthy action of this organ: hence arises one of the most fertile sources of spurious pains, a subject which will shortly come under our consideration. Where the bowels are loaded, in consequence of the pressure upon the ascending cava, considerable obstruction to the free return of blood from the pelvic viscera is produced, the vessels of which become considerably engorged. No organ feels these effects more than the uterus: from the immensely dilated condition of its veins, a state of local plethora is engendered, which, from the congested state of the uterine parietes, considerably interferes with the free and regular action of its fibres, and not unfrequently predisposes to hæmorrhage. Moreover, the rectum being distended with fæces, diminishes proportionally the capacity of the pelvis, and prevents the ready descent of the head into it; occasionally it forms, at the beginning of labour, a solid cylinder of indurated fæces, so hard, as, at the first touch, almost to induce the suspicion of a projecting sacrum. As a measure of common cleanliness, the bowels ought always to be attended to before labour, for, besides the more serious effects now enumerated, the labour may be rendered exceedingly filthy for the patient, and not less disgusting for the practitioner; for, as the sphincter ani loses all power of contraction when the head advances deeper into the pelvis, it follows that whatever fæcal matter may have been lodging in the rectum will now be unconsciously pressed out. Hence, therefore, for the last few days of pregnancy, the bowels should be regularly opened (unless they are so spontaneously, which is seldom the case) by castor oil or other mild laxatives: and if labour has already commenced before this measure has been taken, and if, therefore, there is not sufficient time for the operation of the medicine, an enema should be given.[66] In Germany it is a rule to throw up some chamomile infusion at the commencement of every labour, by which means the process is rendered more cleanly than is frequently the case in this country; and also, for the reasons already given, the early stage is less apt to be tedious from spurious and ineffective pains. _Form and size of the uterus._ The more regular the first precursory pains are, the more symmetrical and uniform will be the shape of the uterus; and again, on the other hand, the more uniform its shape, the more regularly and effectively will it act.