( 449 ) 



XII. — An Investigation into some previously undescribed Tetanic Symptoms 

 produced by Atropia in Cold- Blooded Animals, with a Comparison of the 

 Action of Atropia on Cold-Blooded Animals and on Mammals. By Thomas R. 

 Fraser, M.D. 



(Read 21st December 1868.) 



Authorities on the action of medicinal substances agree in including convul- 

 sions among the effects on man of belladonna, and of its active principle, 

 atropia.* Similar effects are described as occurring when large doses of these 

 substances are administered to dogs, rabbits, and other mammals, and to various 

 birds. The recent remarkable progress of our knowledge of the exact and ulti- 

 mate physiological action of many medicinal substances is greatly due to investi- 

 gations that have been made on animals of a lower type of organisation ; and, 

 accordingly, numerous observers have instituted experiments with atropia on 

 such animals, and especially on frogs. Hitherto, however, convulsions and 

 tetanus have not been described among the effects of atropia-poisoning in cold- 

 blooded animals, f 



While making a series of experiments, in April 1868, to determine the 

 minimum fatal dose of atropia for frogs, I was somewhat surprised to find that 

 symptoms of greatly increased reflex excitability occasionally occurred at a 

 certain stage in the poisoning. Believing that a careful examination of these 

 symptoms might probably serve to throw some light on the causation of several 

 of the complicated effects of a substance that has long occupied an important 

 position as a therapeutic agent, I have made a number of experiments (A), to 

 determine accurately the character of these convulsive effects ; (B), to ascertain 

 the dose necessary for their production ; (C), to differentiate, as far as possible, 



* Christison, " A Treatise on Poisons," 1845, p. 836 ; Trousseau and Pidoux, " Traite de 

 Therapeutique et de Matiere Medicale," tome ii. 1862, p, 55; Pereira, "The Elements of Materia 

 Medica and Therapeutics," vol. ii. part i. 1855, p. 549; Stille, "Therapeutics and Materia 

 Medica," vol. i. 1868, p. 770; Gubler, " Commentaires Therapeutiques du Codex Medicamentai-ius," 

 1868, p. 602 ; Th. and A. Husemann, " Handbuch der Toxikologie," Erste Halfte, 1862, p. 465 ; 

 Tardieu, " Etude Medico-Legale et Clinique sur rEmpoisonnement," 1867, p. 750 ; Taylor, " The 

 Principles and Practice of Medical Jurisprudence," 1865, p. 358; Schroff, " Lehrbuch der 

 Pharmacologic," 1868, p. 508. 



"(■ Since this was written, I have communicated with Dr John Harley, of London (the author 

 of several important papers on the physiological action and therapeutical employment of bella- 

 donna), and have had the satisfaction of learning that he also has observed tetanus, and other 

 symptoms of abnormal reflex activity, in frogs during protracted atropia-poisoning. 



2d March 1869. — I quote the following reference to these symptoms from a work which Dr 

 Harley has published since this paper was communicated :— " The action of atropia leaves the frog 

 in an excessively nervous state ; the least disturbance causes great agitation, with increase of the 

 respiratory movements, and a touch often throws the animal into a tetanic convulsion." — Tin 

 Old Vegetable Neurotics, 1869, p. 240. 



VOL. XXV. PART II. 5 Z 



