We have seen that ergot may be dangerous to the foetus, and further, it may suffice to cause rupture of the uterus. As Jacquemier says, " spon taneous rupture of the uterus is a rare occurrence, notwithstanding the frequent abuse of ergot, and the instances where it has been noted must be explained on the assumption of the presence of alterations in the struc ture of the uterus, old cicatrices, etc., which weaken the natural resist ance of its walls." (Bailly.) Finally, ergot acts on the urinary system by determining frequent mio turition, although the quantity of urine passed is small, accompanied by a sensation of pressure.
It was formerly believed and sustained by Sauvage, Mialhe, Arnal, Hugues (1862), that ergot acted directly on the blood, but this theory is to-day abandoned. Levrat-Perroton, Pereira, Bailly, claim that ergot has a sedative effect on the circulation. The influence of the drug on the heart is not to be doubted. There is slowing of the beats, and Kohler and Eberty have shown that, after the absorption of large amounts, the heart stops in diastole, and remains insensible to all excitation. See has also established that the action of the heart becomes feebler, less frequent, at the same time that it becomes regular, in case of irregularity before the administration of the drug. Finally, Brown-Sequard claims that ergot causes contraction of the vessels of the spinal cord, and of its membranes, and so diminishes the amount of blood circulating in these organs.
As Bernard has proved, the blood-vessels may be either contracted or dilated, the tissues around them either relaxed or compressed, and hence a modification in tension of the blood in the different parts of the vascu lar system.
In 1880, Bailly noted the direct action of ergot on the blood-vessels, and considered it the result of a paralysis of the muscular system of the large arteries. Schneider, Schrenck, Burghardt, Muller, Langius noticed the smallness of the pulse. Spargani, in 1830, claimed that this don of the vessels was generalized throughout the entire vascular system. Admitted by Muller, Parola 1844, Bou jean 1845, See 1846, Levret 1847, Villebrant 1858, Desprez 1860, and later by Gubler, Drasche, Loobel, Dobel, this retraction, this contraction, of the vessels was actually seen by Klebs in 1865, Holmes 1870, and afterwards by Brieseman, Potel, Eberty, Brown-Sequard, Wernich, Vogt, Laborde, Moil, who showed that the diminution in the calibre was due to contraction of the smooth muscular fibres contained within the coats of the vessels. Authorities, however, are not in accord as to the manner in which ergot acts on this smooth mus cular fibre. Some claim that the action is a direct one, such as Holmes, Wernich, Laborde, Petou. Bernard claims that the action is on the
vasomotor centres. On the other hand, Vogt, Kohler, Eberty, Vulpian, claim that the action on the vessels is secondary through the nervous sys tem.
Since the capacity of the vascular system is diminished, there necessa rily results modification in tension. The blood tends to accumulate in the less contracted parts—that is to say, after the administration of ergot, there will be arterial ischlemia and venous congestion in the brain. "If," says Bernard, " we suppose ergotine introduced directly into the vena cave superior or inferior, it will scarcely influence at all these large ves sels, for the muscular fibres are few, and separated by a thick internal coat. After having passed through the right side of the heart and the pulmonary artery, the first elements likely to be influenced are the mus cular fibres in the pulmonary arterioles. As these contract there will result: 1. Increase of tension in the pulmonary artery. 2. The disten sion of the right ventricle will hence be more difficult, and the tension will be raised in the vena cave, which will empty themselves less readily. 3. The pulmonary veins receiving less blood, the left heart receives less, and therefore less is transmitted to the aortal system, and there results diminution of tension in both kinds of vessels." To resume, then, there is increase of tension and congestion in the venous system, and diminution in the arterial. Shortly, however, the er gotized blood will manifest its action on the arterioles of the aortic sys tem; this will transmit less blood to the vena cave system, the tension will increase in the pulmonary veins, until the equilibrium is restored by the cessation of the action of the ergotine.
This modification in tension explains the change in the pulse. Kohler, however, explains the slowing of the heart by an action of ergot on the pneumogastrics.
Finally, ergot also acts on the vessels immediately, by influencing the perivascular tissue. It acts as well on the smooth fibres of the vessels, and on those of other organs, in particular the uterus. As for the mech anism of the contraction, authorities explain it differently. According to Brown•Sequard uterine contractions are subordinate to the vascular con traction. 'The nerves of the uterus are influenced by the anwmia of the medulla, an antemia the result of constriction of its vessels. He accepts, hence, the opinion of Oser and of Schlesinger. Wernich also grants this primal medullary aniemia.
Finally, ergot acts on the nervous centres, and See has noticed verti go, pains in the limbs, cramps, feebleness in the lower limbs.
As for the digestive system, the effects of ergot are, at times, nausea, vomiting, great constipation.