Clinical observations have been more abundant than exact, and a favorable action of the drug in some organic diseases of the heart has been reported; other observers would limit its use to functional arrhythmia, insisting that it is not a substitute for digitalis or aconite, but that it occupies a place distinct from either of those remedies. P. W. Williams[14] recommends cactus for functional heart disease, but, as a rule, found it useless in organic disease. He thinks it one of a class of remedies which act on the accelerator nerves and sympathetic ganglia, shortening the diastole and stimulating the spinal vasomotor nerve centers. Williams apparently relied on Myers for his knowledge of the pharmacologic action, and his paper is a fair example of the clinical studies of cactus. [14] Practitioner, London, 1891, xlvii, 266-273. Ellingwood[15] claims that cactus is a cardiac tonic, acting on the accelerator nerves and heart ganglia, increasing muscular force and arterial tension. He recommends it in both organic and functional diseases. [15] Med. Rec., New York, 1905, lxvii, 857. Boinet and Boy-Teissier found that therapeutic doses of 40 drops of tincture of cactus were without effect on the normal heart. In patients with noisy asystole (_asystolie bruyante_) the same dose produced no appreciable effect. In the period of latent non-compensation of true cardiac patients, from 80 to 100 drops a day increased the force of the failing heart. In patients with secondary heart disease with arrhythmia of nervous origin, daily doses of 80, 100 and 120 drops of the tincture were well tolerated for weeks; they seemed to increase the fulness of the pulse and regulated its rhythm. In spite of such large doses, these observers never noticed any symptoms that could be attributed to a cumulative action. It must be remembered that the precise preparation of cactus which they used is not known. Aulde[16] recommends it as a cardiac tonic free from cumulative effects. [16] Practitioner, London, xlvii, 223; Therap. Gaz., 1890. Gordon Sharp says: “The therapeutics of the subject, I think, are clear enough. Cactus grandiflorus cannot be included in our list of cardiac drugs. It is not even a simple stomachic tonic and at most all one can say is that it has small diuretic action.” Hatcher says: “Clinical testimony is so conflicting that between the extreme views of Gordon Sharp and those of Ellingwood there is room for an honest difference of opinion concerning cactus grandiflorus.” Matthews himself took 100 granules of cactin (1/67 gr.--1 mg. each), 25 every four hours, without experiencing the least effect. CONCLUSIONS Reliable conclusions regarding the therapeutic use of cactus grandiflorus are rendered difficult on account of several factors.