3 a. Barium is reckoned among the poisons which exert local irritating as well as a constitutional action; evidently only because among the symptoms of acute barium poisoning vomiting and diarrhoea are seldom wanting. Since, however, the anatomical lesions characteristic of local irritation are usually absent, and since the symptoms ascribed to it are also, as it appears, observed after the direct introduction of the poison into the blood, we see no ground for endorsing the assumption that B. exerts a local irritating action.
3 b. Concerning the real cause of the poisonousness of the B. compounds we are absolutely ignorant. Judging from the symptoms, their action must be compared to that of the narcotic poison.
3 c. The experiments made on animals prove that the poison exerts an undoubted influence on the circulatory apparatus. Even the older toxicologists called B. a heart-poison, and Cyon had recently demonstrated this property of it by experiments on frogs and rabbits. In mammals cessation of the heart’s action after it has been observed by many, and some have even noted lack of excitability of the paralyzed heart, when irritants are applied to it. The investigation recently undertaken by Mickwitz (Inaug. Diss., Dorpat, 1874.) have defined somewhat more precisely the nature of this cardiac paralysis. Although it is not possible to determine from them whether it is confined solely to the cardiac nerves, or affects also the muscle, still the cessation of action during systole has been shown to be a constant phenomenon both in warm and cold-blooded animals; in cats especially, the cartilaginous consistence of the left ventricle was striking.
3 d. In this connection the parity of action between B. and digitalis cannot be overlooked. The blood-pressure increases enormously after the injection of small quantities of barium solutions into the veins, but the increase is, as a rule, preceded by a not inconsiderable lowering. The increase often occurs very suddenly, and the pressure not infrequently becomes 3 or 4 times as great as before; at the same time the pulse becomes much more rapid. Increasing the dose then causes a steep decline in the pressure curve and paralysis of the heart. Division of the spinal cord in the neck does not at all interfere with the development of this phenomenon, and hence it does not appear improbable that the muscular coat of the vessels, as well as the heart, are affected by the poison.
3 e. The above hypothesis receives support also from the state of excessive contraction into which, as my own investigations show, the smooth muscular fibres of the intestines and bladder are thrown by the poison. Both organs lose their lumen completely in case of B. poisoning. This peculiarity, which can be recognized even during life by the exceedingly active peristaltic movements of the intestines that are visible through the abdominal walls, seems to afford also a sufficient explanation of the diarrhoea and vomiting. It indicates a certain preference of B. for the tissues composed of non-striated muscular fibres, or for the nerves in them, which is characteristic of its action. (BOEHM, Ziemssen’s Cyclamen, xvii, 376.)
4. The experiments of Brunton and Cash show that, locally applied, barium salts act like veratrine on muscle, greatly prolonging the length of its contraction; that they cause rapid contraction of the arterioles, and stop the heart in systole. (Phil. Trans., 1884.).
Hughes was a great writer and a scholar. He actively cooperated with Dr. T.F. Allen to compile his 'Encyclopedia' and rendered immeasurable aid to Dr. Dudgeon in translating Hahnemann's 'Materia Medica Pura' into English. In 1889 he was appointed an Editor of the 'British Homoeopathic Journal' and continued in that capacity until his demise. In 1876, Dr. Hughes was appointed as the Permanent Secretary of the Organization of the International Congress of Homoeopathy Physicians in Philadelphia. He also presided over the International Congress in London.