Transactions of the Royal Society of Edinburgh . o sufficient to explain why different effects are produced infrogs and mammals by different doses of atropia. When a large fatal dose of atropia is administered to a frog, the predominating PRODUCED BY ATEOPIA IN COLD-BLOODED ANIMALS. 483 paralysis is so rapidly and completely produced that no spinal-stimulant symptomcan be exhibited. Death results either from an extreme degree of the paralyticaction, or, possibly, from some other effect of atropia. In neither case, however,does the paralytic action diminish sufficiently (if it diminish at all)
Transactions of the Royal Society of Edinburgh . o sufficient to explain why different effects are produced infrogs and mammals by different doses of atropia. When a large fatal dose of atropia is administered to a frog, the predominating PRODUCED BY ATEOPIA IN COLD-BLOODED ANIMALS. 483 paralysis is so rapidly and completely produced that no spinal-stimulant symptomcan be exhibited. Death results either from an extreme degree of the paralyticaction, or, possibly, from some other effect of atropia. In neither case, however,does the paralytic action diminish sufficiently (if it diminish at all) to permit anyeffects of spinal-stimulation to appear, for death occurs during a high intensityof the paralytic action. Diagram 3 represents an experiment (XLII. of Table I.)in which a large fatal dose of sulphate of atropia was administered to a reflex activity was destroyed in a few minutes, and the conductivity of themotor nerves was completely suspended in one hour and forty minutes. Deathoccurred during the complete paralysis. pzb-. tre t20 tu- Diagram 3.* As the curve of paralysis, op4p8t &c., rises rapidly to the line of completeparalysis, CD, and crossing, terminates above it (at the time of the occurrence ofdeath), while the curve of spinal-stimulation, os4s&, &c, rises with comparativeslowness, it is obvious that no spinal-stimulant effect can possibly be frogs, the only symptoms of a fatal dose of atropia are, accordingly, those ofparalysis, notwithstanding that such a dose exerts a large amount of spinal-stimu-lant action, which is represented in the diagram by the curve os4s8s12, &c. In mammals, fatal doses of atropia invariably produce spasms and at once see why this should be so, if we bear in mind that mammals are lesssusceptible than frogs to a paralytic action. I have delineated in Diagram 4 thesymptoms that were observed in an experiment (Experiment LX.) in which asolution, containing fifteen grains of sulphate of atropia,
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