A text-book of pharmacology and therapeutics; or, The action of drugs in health and disease, . l ganglion, cocaine fails tocause dilatation of the pupil. Several other symptoms are produced by the local application ofcocaine to the eye, at any rate in some instances. Thus, the vesselsof the conjunctiva are much constricted, the eye is more widely openthan usual, so that the white sclerotic is seen above and below theiris; the whole eyeball is pushed forward (exophthalmos), and the intra-ocular tension is said to be considerably reduced. All of these featuresare produced only after cocaine has
A text-book of pharmacology and therapeutics; or, The action of drugs in health and disease, . l ganglion, cocaine fails tocause dilatation of the pupil. Several other symptoms are produced by the local application ofcocaine to the eye, at any rate in some instances. Thus, the vesselsof the conjunctiva are much constricted, the eye is more widely openthan usual, so that the white sclerotic is seen above and below theiris; the whole eyeball is pushed forward (exophthalmos), and the intra-ocular tension is said to be considerably reduced. All of these featuresare produced only after cocaine has been applied in considerable quantity 35G SUBSTANCES ACTING AFTER ABSORPTION and for some time, and may be due, at any rate in part, to its absorp-tion. They may all be observed in the unpoisoned animal when thecervical sympathetic trunk is stimulated, and arise from a specialaction of cocaine on the terminations of this nerve. All of these symp-toms, except the anaesthesia and tiie pallor of the conjunctiva and iris,are produced by the injection of cocaine as well as by its local applica-. Diagram of the innervation of the iris. P, a fibre of the motor ocuH passing from thebrain to the ciHary ganghon A^, in which it terminates around a nerve cell, which sendsan axis cylinder to terminate, AI, in the circular fibres of the iris. R, a spinal nerve fibreissuing from the lower cervical cortl, rvinning through the stellate and inferior cervicalganglia and terminating around a ganglion cell in the superior cervical ganglion, G. Theaxis cylinder from this nerve cell runs to the iris (passing the ciliary ganglion) and ter-minates in fibrils C, on the radiating fibres. C is the point which cocaine stimulates andthe resultant contraction of the muscle fibres causes dilatation of the pupil, but whenstrong impulses descend to M, as happens when the ejc is exposed to bright light, thecircular muscle overcomes the weaker radiating fibres, and the pupil is contracted. Inthe same way strong s
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Keywords: ., bookcentury1900, bookdecade1910, booksubjecttherapeutics, bookyea
