634 



PHYSIOLOGY. 



tolic dilatation, depend entirely on the relative 

 quantity of the normal saline constituents of 

 the blood. With calcium chloride added to 

 the saline, if the rhythmic contractions retain 

 their normal frequency, we get increased 

 breadth with rounding of the top of the trace, 

 which leads to fusion of the beats, and the trace 

 rises high above the top of the base-line. The 

 effect of adding potash salt to the circulating 

 fluid is to remove lime effects and restore good 

 normal conditions. If the contractions are 

 less frequent, or occur only with an excitation, 

 the calcium chloride, like other lime salts, at 

 first broadens the trace, rounding its top, and 

 then greatly retards diastolic dilatation. Potas- 

 sium chloride obviates these effects. The ef- 

 fects may be modified by introducing potas- 

 sium bicarbonate, or by varying the amount of 

 calcium chloride in the circulating fluid; but 

 with a sufficient quantity of potassium chloride, 

 no quantity of calcium chloride is capable of 

 retarding diastolic dilatation. 



The Nervons System. From observations made 

 upon dogs, to determine the connection of the 

 semicircular canals with the function of equili- 

 bration, Bechterew has concluded that unilat- 

 eral section is followed by forced movements 

 of rotation around the axis of the body, with 

 deviation of the eyes, nystagmus, etc., which 

 movements are at first constant, but occur later 

 in paroxysms separated by periods of rest. 

 During the intervals between the paroxysms, 

 the animal assumes a constrained position, ly- 

 ing on the opposite side to that of the section. 

 The rolling movements finally cease, but the 

 tendency to exhibit circus movements toward 

 the injured side continues, while the animal is 

 deficient in power to maintain its .balance on 

 its feet. These symptoms are reflex, for they 

 are still exhibited after removal of the cerebral 

 hemispheres, or in narcosis; but they are more 

 marked when the hemispheres are present. 

 Section of both auditory nerves is accompanied 

 by marked deficiency of the power of main- 

 taining equilibrium, so that the animal can 

 neither stand nor walk. The forced move- 

 ments when only one nerve is cut are due to 

 the disharmony resulting from the presence of 

 the normal semicircular-canal sensations on 

 one side and their absence on the other. The 

 balance is destroyed, and vertigo results. The 

 well-known action of auditory impressions in 

 influencing movements, as in dancing and 

 marching, is thought, from these experiments, 

 to occur through the semicircular canals. 



In subsequent experiments Bechterew found 

 that the central gray substance of the third ven- 

 tricle forms an organ of equilibration in the 

 same sense as the semicircular canals and the 

 olivary bodies. Having prepared his subject 

 so that a section could be made of the gray 

 matter in any desired direction, he found that 

 injury to any portion of that substance in the 

 third ventricle was always followed by dis- 

 turbances of equilibrium similar, in a general 

 way, to those caused by section of the semi- 



circular canals. Disturbances of equilibrium 

 which have been noticed by other observers 

 after sections in this region, but which were 

 attributed to other parts, were, in Bechterew's 

 opinion, probably caused by injury to the walls 

 of the third ventricle. The presence of bodily 

 equilibrium is brought about, according to this 

 observer, by the action of three peripheral equi- 

 librium organs; viz., the semicircular canals, 

 the gray matter of the third ventricle, and the 

 olivary bodies of the medulla. Each of these 

 organs, it is interesting to notice, is not only 

 connected with the cerebellum, through which 

 it acts on the muscles, but is closely related 

 also to one of the higher sense organs : the 

 olivary bodies, to the skin; the semicircular 

 canals, to the ear; and the gray matter of the 

 third ventricle, to the eye. The intimate con- 

 nection existing between the organs of sight 

 and equilibrium is known to all; and this con- 

 nection depends not so much on the visual sen- 

 sations as on the position of the eyeballs. In- 

 jury to the center in the third ventricle was 

 always followed by marked changes in the di- 

 rection of the axes of the eyeballs; and the 

 author suggests that changes in the position of 

 the eyeballs may, in their turn, act as mechani- 

 cal stimulus to this center. 



Experiments on dogs by Bochfontaine go to 

 confirm the view of Flourens, ascribing vica- 

 rious functions to the cerebral convolutions. 

 At one time electrical stimulation of a particu- 

 lar surface area, , may. for example, be fol- 

 lowed by a secretion of the submaxillary gland, 

 or by some definite movement of a limb, while 

 the same stimulus, applied to other regions of 

 the cerebral surface, has no such consequences. 

 In half or three quarters of an hour the region 

 a will, however, cease to react to stimuli, while 

 some other area, J, previously inexcitable, be- 

 comes irritable, and its stimulation is followed 

 by the same phenomena as resulted from the 

 stimulation of a. Bochfontaine suggests that 

 the gray rind is itself not capable of electrical 

 excitation, and that the result is always due 

 to direct stimulation of subjacent medullated 

 nerve-fibers. A bundle of such fibers, all with 

 the same peripheral connection, may subdivide 

 in the brain, and end in three or four different 

 regions of its surface. 



Dr. Seymour J. Sharkey, of St. Thomas 

 Hospital, London, has described a number of 

 cases within his practice bearing upon the sub- 

 ject of cerebral localizations, in the light of 

 which he makes the statement that although 

 there may be slight differences of opinion as 

 to the exact limitation of the cortical centers, 

 recorded cases present a striking agreement 

 with regard to the most important facts. The 

 conclusions which appear to be warranted from 

 our present experience are : 1. That there are 

 cortical centers, and that they are situated in 

 the two ascending central convolutions, and 

 in the convolutions adjacent to them on the 

 internal aspect of the hemispheres. 2. That 

 the centers for the arm, leg, and face are more 



