The vascular system, through the agency of the nerves, is profoundly affected, as already shown. Spasm of the muscles of the bladder and rectum is sometimes present, and in some cases is distressing and lasts for a considerable time. Symptoms resembling those produced by malaria are occasionally found. Levenstein, who was the first to call attention to this, says: “Intermittent fever, in consequence of a morbid craving for morphia, seems to be due to a certain neuropathic disposition, as it does not show itself with many patients, although they have taken large doses of the drug, and for years together. It was, however, impossible to fix on any other cause for the development of intermittent fever but the use of morphia, as the respective patients lived in regions free from malaria, and as none of the other members of the family living under the same conditions showed any similar symptoms. “We may distinguish a light and a severe type of intermittent fever, when brought on by a morbid craving for morphia. Both forms resemble real malarial fever, inasmuch as the first paroxysms, occurring at regular intervals, seemed to disappear after the use of quinine, returning, however, very soon, although the febrifuge was continually given; that, furthermore, they were improved by change of air, but came on again from the simplest causes, such as boating, errors of diet, etc. “The characteristic symptoms of this fever are the same as those caused by malaria: chilly feeling, up to regular shivering, headache, oppression, heat and perspiration. They differ from one another in this respect, that immediately the morphia is discontinued, the attacks disappear without any treatment, although they may have existed a long time. “In some cases the intermittent fever sets in in an erratic manner. The patient, at irregular times, experiences an attack of fever, with chill, heat and sweating. These attacks occur from three to six times, at long intervals, not showing themselves hereafter any more at all, or only after a great lapse of time. In most cases the attacks of intermittent fever, in morbid craving for morphia, shows a tertian, rarely a quotidian, type. They are sometimes ante-, sometimes post-ponent. The attacks last from four to ten hours, and are followed by a normal condition. “The paroxysms disappear only in exceptional cases, without the morphia being stopped. In this case the patients complain of experiencing an uncomfortable sensation, principally of an exhausting character, at the usual time of the attacks.