Valentin on the functions of the nerves of the orbit / translated from the Latin by John F. France.
- Gabriel Valentin
- Date:
- [1846]
Licence: Public Domain Mark
Credit: Valentin on the functions of the nerves of the orbit / translated from the Latin by John F. France. Source: Wellcome Collection.
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![upon stronger stimulation being em¬ ployed. The circumstance observed by Zinn* * * § and Langenbeckf, that the iris becomes contracted upon escape of the aqueous humour, appears unconnected with this point; for every time I have repeated the experiment on the dog, though the pupil has contracted, yet the animal has become so strongly affected by moderate day-light as to be obliged to search for a dark place, and the pupil has again dilated when this has been gained. Hence it would seem that the contraction was not so much from a direct action upon the nerves of the iris, as from the excessive effect of light upon the subjects of the operation, and consequent reflex action flowing from the retina upon the motor fibres of the iris. According to Haller|:, Fontana §, and Magendiej], mechanical irritaion of the iris has no effect upon the membrane: but the fact is, that in living animals the experiment is ambiguous, because morbid irritability of retina arises from the operation. The freshest^ bodies of animals are alone fit for this experiment; and in them strong irritation of the iris, whether me¬ chanical, chemical, or galvanic, ex¬ cites an alteration of pupil; not rapidly, indeed, as in muscles with compound fibres, but slowly, as hap¬ pens in organic muscles. Hence, how¬ ever, it is evident that the sentient fibres contained in the ciliary branches are capable of exciting motion of the iris, by reflex action from the nervous centre. 4th. It has been fully explained already, that diminution of the pupil is connected with the action of the inferior division of the motor oculi; and that upon the action of the superior division of the same nerve, the pupil either remains unchanged or rather becomes dilated. 5th. We have also shewn that the motor fibres, whether contained in the ciliary nerves or ganglion, or in the inferior division or trunk of the motor oculi, cause motion of the iris directly. * Observ. circa diif. oc. hum. et brutorum, Comm. reg. Soc. Gotting-. t According to Palmedo. Part. sens, et irrit. § Natur d. tbier. Koerpers. II Phys. vol. i. % Even these, however, are only available provided the pupil is not at all paralytic from death, and possesses a certain considerable degree of irritability. Finally, the pupil contracts when the cervical portions of the vagus and sympathetic are divided, in dogs or horses, and in a less degree in rabbits. Of this important fact. Petit* was the original observer, who instituted the first experiments relating to the subject in the years 1/12 and 1725. Having persuaded himself that the sympathetic nerve sends the animal spirits upwards to the eye, he divided the conjoined cervical portions of the vagus and sympathetic in a dog; and always found after this, the cornea of the same side lessened in brilliance, dull, and flattened; the fold of con¬ junctiva drawn out, an increased flow of tears, and coarctation of pupil. These symptoms had, in one case, entirely subsided in two months; in another, to a certain extent, in twelve days. When the vagus and sympa¬ thetic were divided on both sides, the pupils were unequally dilated. Molinellif, who tied the sympa¬ thetic and vagus, confirms these statements; but Arnemannj:, though after division of the vagus in dogs, he observed increased lacrymation, and morbid sensibility and inflam¬ mation of the globe, with muddi¬ ness of the cornea and mucous dis¬ charge covering it, and extension of the fold of conjunctiva, yet, ex¬ pressly denies any alteration of pupil. Dupuy§, together with Dupuytren and Breschet, found the pupil con¬ tracted and the blood-vessels of the conjunctiva distended, after division of the superior cervical ganglion of the sympathetic. Mayer|l, again, in so many words, asserts this influence of the cervical portions of the sympa¬ thetic and vagus upon the globe; but Brachet, who instituted a multitude of experiments upon the vagus and sym¬ pathetic, makes no separate mention of the stale of the pupil. Lastly. Arnold^y» who observed diminution of pupil follow the operation of dividing the vagus and sympathetic nerves in dogs, and disappear again in four or five months, considers the latter phe¬ nomenon a certain indication of re- * Hist, de I’Acad. Paris, 1727, 1729. t Comment. Bonon. vol. iii.; and Burdach, Geh. vol. iii. $ Versuche iib. die Reg-en. Ami. i. § Jour, de MM. vol. xxxvii.—Lund, Vivis. 11 De arter, reg'en. 1823.—Graefe and Wultlu Jo urn. A'ol. X. Bemerkun^en.](https://iiif.wellcomecollection.org/image/b30798115_0032.jp2/full/800%2C/0/default.jpg)
