Few of our readers are probably aware of the remarkable vertiginous conditions which they can artificially induce in their own persons. Purkinje, the well-known anatomist and physiologist, Was the first who brought these remarkable facts within the range of experimental science in two memoirs published in 1820 and 1827. Vertical vertigo is thus produced. The experimenter—who must be standing—has a somewhat heavy weight attached to each hand, and as be carefully watches the sensation produced by gravitation for sonic time, lie feels the weights growing heavier and heavier, till lie can no longer bear them. On putting them down, when he feels he can bear them no longer, It appears to him as if he was impelled to mount straight upward, and as if the arms were shortened, and the hands must creep up to the thorax. Similar experiments with she muscles of the eye afford still more striking results. "If the face," says Purkinje, ' be turned to the ceiling, and the eye be fixed on a given point, round which, as the ....tile of a vertical axis, the body is turned a certain number of times, the visible objects if the ceiling, as well as the floor of the room, will, if the position of the head and the direction of the eyes be maintained, appear to move in a horizontal direction. If, dur Lug- the proceeding, the head be brought back into the ordinary upright position, the horizontal will be turned into vertical and this sensation will be communi to the tactile sense of the hands and feet, the floor appearing to sink down on one side, and to rise on the other."—See Rust's Magazine, etc., 1827, vol. xxiii. p. .
An analogous effect is produced by on the brink of, or in, a running stream, and fixing the eyes on the water; after a time, the sensation begins all at once of being borne along against the current. When this sensation comes on in wading in a river, it is very difficult to keep one's feet; and hence it is dangerous to let the eyes rest on the current close by.
Hitherto, we have spoken of vertigo, merely as a sensation; but there are certain morbid conditions of the brain, and certain operations which experimental physiologists can perform upon it, that will give rise to what may be termed vertiginous movements, if we include under the term vertigo straight as well as circular movements, as is usually done by writers on this subject. From the experiments of Magendie and Flourenk
which have been confirmed by Krauss and Hertwig, it follows that: 1. Removal of both copora striata of the brain induces an irresistible tendency to advance, the animal shoot ing straight forward like an arrow; 2. Slicing the cerebellum, whether horizontally or vertically, causes the animal to walk backward; 3. Section of the corpora quadri gemina of one side, and of one side of the pons varolii, excites rotatory movements and gyrations of the animal toward the injured side; while division of the corresponding parts on the opposite side restores the balance. Vertiginous movements consequent on disease w4re descnbed by the veterinary surgeons in sheep before they were noticed in the human subject. The eanurus eerebralis, which is now known to be the larva of a species of tapeworm (tania eanurus) infesting the dog, is the well-known hydatid in the brain of sheep, producing in that animal the disease known under the various names of staggers, turu•sick, goggles. rotatory disease, etc. How this hydatid excites these move ments when it destroys certain parts of the brain, is now explained by the experiments previously noticed. Dr. Romberg has collected a number of very interesting cases of vertiginous movements in the human subject.—On this subject, in addition to Romberg's work, the reader may consult a paper by Dr. Paget, " On Morbid Rhythmical Move ments," in the Edin. Ned. and Sum, Jour , 1847, vol. lxvii.; and the remarks of Dr. Carpenter (in criticism of some of Magendie's conclusions) on the cerebellum and its functions in his human physiology.