564 



PHYSIOLOGY. 



The idea has often been put forward that where 

 an organ has a nerve-supply from two sources, 

 the two sets of nerves must have actions which 

 are physiologically antagonistic. The results 

 made known in a paper by C. H. Fagge detailing 

 researches on the innervation of urinary passages 

 in the dog, taken in conjunction with previous 

 work by other observers on the same subject, 

 show that, in the case of those organs, the dif- 

 ference between the two sets of nerves (sympa- 

 thetic and sacral) is morphological rather than 

 physiological. 



Narcotic effects have been found by Dr. Her- 

 mann Beyer to be exerted by odorous substances 

 on the sensory and motor nerves of the frog. 

 When the animal was made to breathe air charged 

 with odors, the succession of events resembled 

 that of chloroform narcosis in there occurring 

 a preliminary state of excitation followed by 

 motor and sensor paralysis. A considerable num- 

 ber of the substances experimented with, which 

 are named in the author's paper, acted quickly 

 and strongly, while others were less active. The 

 frogs were placed near a sponge or wad wet with 

 the odorous substance, but not in contact with it. 

 Heat, respiration, and muscular power were af- 

 fected. Special experiments indicated that the 

 absorption of vapor is effected to a larger extent 

 by the skin than by the lungs, and that the im- 

 paired excitability and coordinating power result- 

 ing have a central origin. Experiments on the di- 

 rect action of odorous substances showed a loss of 

 excitability on the part of the nerve exposed, ex- 

 tending gradually upward and more slowly down- 

 ward. 



Special Senses. A communication has been 

 published in the New York Medical Record by 

 Prof. G. E. de Schweinitz on Deleterious Results 

 of Certain Common Drugs and Narcotics on the 

 Organs of Sight, in which the results of obser- 

 vations of the author's practise during recent 

 years in the ophthalmological department of the 

 Philadelphia Hospital are recorded. The most 

 important form of functional visual defect or am- 

 blyopia noticed was produced by quinin. It was 

 manifested in different ways and degrees varying 

 with the doses and with the idiosyncrasies of the 

 patient. With moderate doses, temporary dimness 

 of sight occurred. When the doses were large 

 (60 to 80 grains a day), the affection assumed 

 a second and more serious form. Blindness of 

 sudden onset and almost complete in degree re- 

 sulted, and lasted several days. Ophthalmoscopic 

 examination showed great pallor of the optic 

 disks and blanching of the retina. Quinin in 

 large doses also had toxic effects on the ganglion- 

 cells of the retina. This quinin blindness is de- 

 scribed as similar to that caused by salicylates 

 or by antifebrin, and the actual changes are very 

 similar. lodoform when absorbed from dress- 

 ings of wounds and burns, or after administration 

 by the mouth, occasionally produced amblyopia. 

 Alcoholic amblyopia was produced by ordinary 

 alcohol, and in a more intense degree by methyl 

 alcohol; and substances in which methyl alcohol 

 was an ingredient had a similar effect. Certain 

 strong forms of tobacco, particularly if smoked 

 in a pipe or on an empty stomach, were specially 

 liable to give rise to amblyopia. Usually, Iiow- 

 ever, several years passed before the vision was 

 thus affected; while an indescribable haze or fog 

 Beemed to obscure the view. Pallor of the optic 

 disk and central scotoma for red and green in 

 the field of vision were observed. If the patient 

 was intemperate, the disease progressed more 

 rapidly. The histological investigation showed 

 that the retinal ganglion-cells in the macula lutea 



underwent degeneration; and some change could 

 be detected in the macular fibers of the optic 

 nerve. Which of the active principles in tobacco 

 was the actual agent was not determined. 

 Among the forms of amblyopia due to occupa- 

 tion were those occurring among lead-workers 

 and india-rubber workers (in whom the effect 

 was produced by the carbon disulfid used as a 

 solvent for the rubber). Amblyopia was also met 

 with as a result of being exposed to or inhaling 

 fumes of nitrobenzene or dinitrobenzene, a sub- 

 stance which is produced in chemical factories, 

 and is commonly known as essence of almonds. 



The photosensitive pigment, or visual purple, 

 which is supposed to belong to the rods only, and 

 not to be present in the cones, has been found 

 by Dr. F. W. Eldridge Green present in the cen- 

 tral region of the retina, in which there are cones 

 only and no rods. On examining the retina of 

 the monkey when the animal had been kept in 

 the dark for twenty-four hours in order to in- 

 crease the amount of visual purple, the central 

 region of vision, the yellow spot, instead of being 

 free from the pigment, was the most purple spot 

 of the whole retina. The purple was, however, 

 seen by microscopical examination to be around 

 and not actually within the cone. The author 

 advanced the theory that the cones were sensi- 

 tive only to changes in the visual purple, not to 

 light itself. 



At the annual meeting of the British Medical 

 Association Dr. F. W. Eldridge Green described 

 his view of the origin of a visual impulse as being 

 that light falling upon the retina liberated visual 

 purple from the rods, and this, being acted on by 

 light, stimulated chemically the cones and an 

 impulse was transmitted along the visual path 

 to the brain and received by a light perceptive 

 center which did not appreciate color but sim- 

 ply light and shade. Color perception was due 

 to a special center separate from the visual cen- 

 ter, but closely connected with it, a color being 

 simply a point of difference capable of being 

 seen by this center. 



Observations are described by Dr. C. S. Myers 

 as having been made by means of tuning-forks 

 concerning the smallest musical tone-difference 

 perceptible to the people of Scotland and those 

 of Torres Straits. But little difference in the 

 original capacity to distinguish tones was found 

 between the children of Murray island and those 

 of Aberdeenshire ; but with practise the Scot- 

 tish children improved very rapidly and uni- 

 formly. The adult Murray Islanders for the 

 most part failed to detect intervals of a semi- 

 tone. The average difference of frequency of 

 vibration just distinguishable by them was 15 

 vibrations per second : while for the adult Scotch 

 examined it was 9 vibrations. 



In the third volume of the Journal of Physiol- 

 ogy, p. 22, Sir W. R. Gowans described a case of 

 disease which suggested strongly that the path 

 for taste reaches the brain by the roots of the 

 fifth nerve, both as regards the front and the 

 back of the tongue. Since the article was pub- 

 lished the author has met with strong confirma- 

 tory evidence from cases of disease. But he re- 

 gards such evidence as unimportant when com- 

 pared with the proof of the fact supplied by the 

 modern surgical procedure of the removal of the 

 Gasserian ganglion and the adjacent part of the 

 fifth nerve, known as Krause's operation for 

 neuralgia. Five cases of operations are adduced 

 in the author's paper in the Journal of Physi- 

 ology (vol. xxviii, NO. 4), 4 cases by Mr. Hors- 

 ley and 1 by Mr. Ballanee, these being the last 

 consecutive cases in which the operation was 



