PHYSIOLOGY. 



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perreive \\llirll pole was l|lj)lif(l to the eye. Oil 



KM other hand, the retina responded much less 

 readily lu di.-c barges from condensers or induc- 

 tion coils. 



l>r. ('. L. Herrick, in the American Assoeiu- 

 tion. presented the case of a supposed tubercu- 

 lar disease of the eye of u cat. which was shown 

 by a'.stopsy to lie accompanied l>y a tniirked 

 degeneration in that part of the l>raiu in the 

 nei-ipiial lulie which is supposed to In- connected 

 with the organ of vision. Another confirmation 

 is thus a (To rded of the theory of cerebral local- 

 ix.at ion. 



From the necropsy of a right handed-woman 

 who hail been word-deaf for fifteen years, and 

 deaf and partially paraly/.ed for nine years. Dr. 

 ( '. K. Mills thinks he is justified in contending 

 that the center for word-hearing is situated in 

 the hinder third of the first and second temporal 

 convolutions, and is possibly restricted to the 

 second, and that, although the auditory cerebral 

 arrangements have their chief development in 

 the left temporal lobes, destruction of the opposite 

 center is necessary in order to abolish hearing 

 entirely. 



Muscular System. It has been observed by 

 Dr. John Berry Have raft that where a muscle is 

 stimulated by an electrical shock all the fibers 

 of the nerve receive the same stimulus and all 

 the fibers of the muscles to which the nerve 

 passes contract together and in the same way. 

 Tliis is not the case when a muscle contracts on 

 receiving a natural nerve stimulation. The cen- 

 tral nervous system seems unable to affect all 

 the fibers of a muscle through the numerous 

 nerve fibers passing to it in such a manner that 

 they all shall contract exactly in the same way. 

 This is supposed to be the case from the fact 

 that fascicular movements are always present 

 within a muscle during a voluntary or a reflex 

 contraction, so that tracings taken from differ- 

 ent parts of the same muscle invariably differ 

 from one another. These fascicular movements 

 occurring within it will prevent any muscle from 

 pulling with perfect steadiness on any lever or 

 other registering apparatus, and the tracings 

 taken by means of such apparatus will show os- 

 cillatory waves, often very rhythmical in their 

 appearance. Many observers have concluded 

 from an explanation of these tracings that they 

 indicate that the central nervous system dis- 

 charges impulses into the muscle at a rate cor- 

 responding with that of the oscillations observed. 

 The author finds that the fascicular movements 

 account fully for the oscillations ; he suggests, 

 also, that they probably account for the produc- 

 tion of the muscle sound, which Helmholtz has 

 pointed out was chiefly an ear-resonance sound. 



As the results of research made several years 

 ago, Prof. JIaycraft believes that the cross-strip- 

 ing of a muscle depends on the moniliform divis- 

 ions of the muscular fibrils, and not on their 

 structure. In later experiments lie took castings 

 of muscular fibers, assuming that if the casts 

 should exhibit the microscopical appearance of 

 the muscle those appearances could IK> due only 

 to its form. After several trials he found the 

 most satisfactory method to be that of stamping 

 moist collodion with fillers. A drop of collodion 

 was placed upon a glass slide, and before it was 

 quite dry some muscle fibers were pressed upon it 



with the finger*. Thww were then removed, and 

 the film, mi being examined with tin- -| < ir 

 was M-n to in- i-nvi-ri-d by i-xqiiiftite iiiipri*utiorw 

 of the filnT. K\ery Mri|*' waa clearly and .hitr|.|y 

 defined. When the collodion dried tl,. 

 shrank and the little im previous disappeared. 

 The castings showed the microscopical appcitr- 



aii< f the filler in whatever stage of contraction 



or relaxation it might happen to In-. 



To the usual well-known timnlating 



muscles to contraction vi/... electrical, thermal, 

 mechanical, and chemical M. d'Arsonvul has 

 recently added that by means of light. He could 

 not, indeed, get any contraction in a fresh 

 frog muscle when lie suddenly threw bright 

 light upon it in a dark chamber: but. having 

 first in darkness stimulated a muscle with induc- 

 tion currents too weak to give a \isible 

 and then suddenly illuminated the muscle with 

 an arc light, the muscle showed slight t reinitia- 

 tion. Not thinking this conclusive, however, 

 M. d'Arsonval attached a muscle to the middle 

 of a piece of skin stretched on a funnel, and con- 

 nected the tube of the funnel by means of a 

 piece of India-rubber tube with the ear. The 

 muscle being now subject to intense intermittent 

 light, he heard a tone corresponding to the 

 period of illumination, and this ceased when the 

 muscle was killed by heat. 



The origin of the croaking or grunting noise 

 made by the perch (Haplvitlunotnx 1/1 ntmii-us) has 

 l>een investigated by Dr. \V. H. Hamilton. The 

 fish is furnished with a masticatory- apparatus 

 in the gullet, of which the lower division has a 

 flat, triangular upper surface, studded over with 

 spheroidal processes answering to teeth ; while 

 the upper division is composed of two parts 

 united by a lignment. the lower surfaces of 

 which are supplied with similar teeth. The 

 divisions of this apparatus are furnished with 

 powerful muscles by which they can be pressed 

 together and moved rapidly on each other. By 

 this process the fish masticates the crustaceans 

 on which it feeds, and the croaking is produced 

 by the teeth coming in contact. 



Herr Meyer, of Hamburg, denies that ventrilo- 

 quism consists in speaking while inspiring and 

 without the cavity of the mouth acting as a 

 resonator. On the contrary, be says ventrilo- 

 quists speak while expiring a. d move their 

 mouths. Laryngoscopic observations on the 

 author, who practices the art. showed that in 

 ventriloquixing the vocal opening of the larynx 

 is shortened as it is when producing the false! to, 

 and that the soft palate is pressed imck and the 

 uvula becomes invisible. The graphic record of 

 experiments made by Prof. Gad on Herr Meyer 

 showed that the curve obtained when a certain 

 sentence is spoken in the ordinary w y is identi- 

 cal with the one which is described when the 

 same sentence is spoken vcntriloqniallv. In the 

 latter ca-e the volume of air expired w;i- 

 than during normal speech. Dr. Benda believes 

 that when vcntriloquixing the Eustachian tuln-s 

 are open, and the cavity of the tympanum, to- 

 gether with the tympanic membrane, are >et ir.to 

 simultaneous vibration, for the curious veiled 

 tones of ventriloquism resemble the ton- - 

 duced by speaking while yawning, and then tho 

 Kustachion tid>es are certainly open and the 

 tympanic cavity acts as a resonator. 



