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OPHTHALMOLOGICAL SOCIETY OF THEUNITED KINGDOM.

fi-oiii Optic i%7-euritis. -Congenital Anomaly in

I’Ciioz:-sl3ot Ptegioit. - Blood- clot behind lris.- Colo1lr-I e’,Z (t71, CSS.

A SPECIAL meeting was held on the 7thinst., W. Bowman<Es., F.R.S., President, in the chair, the main businessbeing the presentation of a report of a committee uponcolour-blindness, which was read by Dr. Brailey. At the

close of the meeting a demonstration on the subject wasgiven.

Dr. HUGHLINGS JACKSON showed a case ten years after

recovery from Optic Neuritis. The patient came under careten years ago for cerebral disease, seizures beginning in theright cheek, followed by right hemiplegia and temporaryaphasia, and neuritis. The disease was due to syphilis,and under iodide of potassium recovery took place. The

patient now complains of some numbness in two fingers- of the left hand. His optic discs appear normal; one

could not say from examining them that there had beenneuritis. Vision too is normal.Mr. WAREN TAY showed an infant, aged twelve months,

who was brought to the London Hospital for weakness ofits back and limbs. Suspecting some cerebral affection(congenital) the optic discs were examined with the ophthal-moscope. They were found to be healthy, but on the yellow-spot region of each eye was a conspicuous white patch ofconsiderable size, with a brownish-red fairly circular spotin the centre. The conditions somewhat resembled thosemet with in the yellow-spot region in cases of embolism ofthe central artery. The changes are probably situated inthe retina, and are possibly congenital. There were no signsof syphilis whatever; a sketch of the fundus of each eyewas exhibited.-Mr. BRUDENELL CARTER suggested thatdie appearance was due to some opacity of the connectivetissue around the fovea centralis, leaving a space throughwhich the choroid was visible.-Mr. TAY said the yellowspot itself certainly seemed to be healthy. The condition’had not altered during the six weeks it had been underobservation.The PRESIDENT showed for Mr. Power a case of Haemor-

rhagic Clot behind the Iris, the clot having remained un-altered for some months. The humours were clear, butthere was a dull reflex from the fundus suggestive of deepe]effusion. Mr. Bowman remarked that blood-clots in th{eye often remained unchanged for many months-e.g., irdiabetes. In this case the iris looks normal. The eye &Iuml;Ivery nearly blind.The Report on Colour-blindness was then presented for i

Committee of the Society by its Secretary, Dr.W. A. BRAILEYBy the aid of sixteen colleagues 18,088 persons have beerexamined, of whom 1657 were females. The average perventage of colour defects among these latter was ’4, that othe males being 4’76, the pronounced cases only amonmales being 3’5 per cent. Certain classes of persons shovan exceptionally high percentage of colour defects. Thmost striking in this respect are deaf-mutes, among whonevery fifth child is defective. The average is also highethan normal among members of the Society of Friendsespecially among those belonging to the poorer classes. Iis distinctly high among Jews, and the forms of colouiblindness occurring among these are very pronouncedThere is also observed a diminution in the percentage (

colour-blindness as we ascend in the social and educationscale. For example, at Eton (769 boys) the percentage (

pronounced cases, which are the most reliable for purpos{of comparison, is2-46. Among medical students and sons (medical men (435 persons) it is 25. In middle-class Londoschools (2671 boys) it is 3-48. In the Metropolitan police (49amen) it is 3’52. Among poorer schools in London (1729 boys3-87. There appears to be no excess of colour defects amorlunatics, or in town, as distinguished from rural populationThey are perhaps greater in Ireland than in England. Athe pronounced cases reported (red and green blinds), nl

only make mistakes in the matching of coloured woolbut are unable to distinguish the colours of red and greElights; though sometimes, when they are contrasted si<by side or in rapid succession, they are enabled to gue

;hem by the fact that with equal illumination one appearsto them always brighter than the other; but if their bright-ness and distance be unknown they are utterly unable todistinguish between them. Certain remarks were added byDr. Brailey as to (1) the causation of colour defects, and(2) as to the mode in which the red- and green- blind see thesecolours. He attributes colour defects in some cases to acongenital physical defect, either in eye or brain, occurringas an accidental variation from the normal structure. Whenonce existing it is capable of being transmitted to descend-ants. In other cases he thinks that they may arise, moreespecially the slight forms, from defective education incolours in infancy. This might account for the superiorityof the female sex in respect to colours. Though brought upin very early life under the same circumstances as malestheir different tastes lead them to a greater study of colours,which will be facilitated by their more rapid mental de-velopment, especially in the observing faculties. It wouldalso account for the high percentage exhibited by the deafand dumb, and to some extent for that of members of theSociety of Friends. It would also be compatible witha greater prevalence of colour defects among the poor.The third factor, which is by no means an unimportant one, isintermarriage. He is strongly of opinion that among Jews,and to a less degree among Friends, intermarriage duringgenerations has strengthened the defects existing amongthem not only in number but in degree. In connexion withthis it is important to notice that red-blindness, which heconsiders a more aggravated form than green-blindness, isespecially prevalent among Jews, and, to some extent, amongFriends also. He suspects an unduly high average of colourdefects among the children of those working in colours, such asartists, dyers, &c., though he has as yet not collectedsufficient evidence to establish the position on a statisticalbasis. With regard to the question as to what those blindto red and green see in place of these colours, he thinksthat they appear to them as shades of grey, either pure ormixed, with a little of yellow. The completely green-blind probably sees pure green as a pure grey of the sameshade. Red he sees as a dull yellow-brown, of a shadesimilar or slightly darker than the red is to a normal eye.Therefore he will more commonly match green with greyand red with yellow-browns, or with a green that is slightlyyellowish. The completely red-blind sees green as a greytinged with a little yellow, but of similar shade. He seesred as a very dull yellow-brown of much darker shade thanthe red is to a normal person. Therefore he will match redwith a much darker yellow-brown, or with a much darker

, slightly yellowish-green. He will match green with.

grey less often than the green-blind. He thinks thatin red and green blindness there is also a slightlyL defective appreciation of all colours, so that all pale shadest are liable to be confused, especially at a distance, or

by artificial or deficient light.-Mr. FROST mentioned a fact bearing on the hereditary transmission of colour- blindness.. The father, a draper, was so colour-blind as to be obliged tomark the colour of all his goods. Of his seven sons, six-were known to be colour-blind ; but none of his threef daughters were ; one of them, however, has a son who is com-; pletely red-blind; and being a jeweller is unable to distinguish{ between rubies and emeralds.-Tbe PRESIDENT was not3 previously aware of the prevalence of colour-blindness in thei Society of Friends. Dalton was a Friend and he mentionsr a brother of his who was also colour-blind. It was also in-, teresting that among this society both sexes seemed equallyt prone to the defect. The influence of education had been- also seen in reports in other countries. As the object of this.. inquiry was to induce the Board of Trade to institute ex-If aminations of officials concerned in signalling, &c., the value

of a report based on 18,000 cases was great. It was interest-)f ing to find its results agree with those obtained elsewhere,;s and especially with the more recent investigations; for in)f Norway and Denmark recent observations (made undern improved experience) had not tallied with earlier ones.

:2 There appeared to be but few cases in which only one), eye was colour-blind. We are still only at the openingg of the inquiry upon the nature of colour-blindness.-s. Mr. BRUDENELL CARTER thought that all cases of mono-11 cular colour-blindness would escape notice under the present)t plan of examination. When one considers that anisome-s, tropia is not uncommon it seems likely that many cases,

!n especially those which are hereditary, may be met with.ie He expressed the great debt which the Society and thess public owed Dr. Brailey and his coadjutors for this arduous

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investigation; of its importance there could be no questionwhen one considered that one railway company (the Londonand North Western) alone employs about one thousandengine drivers, of whom forty-five must be colour-blind.This would illustrate the great perils incurred, and suggestedthat many accidents may be due to this hitherto unknownand unappreciated cause. It was most important, then, toget legislative recognition of the subject.-Mr. M’HARDYhad found that engravers were often colour-blind, and somehad not taken to engraving for this very reason. He askedwhat was the highest percentage of colour blindnessamongst any particular class of the Friends’ children. Onthe Connecticut Railway at least one per cent. of theemploy&eacute;s was found to be colour-blind; many such getdischarged from work on account of mistakes attributed tocarelessness, &c. He referred to the case of a collision inNorfolk Harbour, U.S., where there was cross-swearing asto the colour of the lights; when the pilot was found,three years subsequently, to be colour-blind, and incapableof distinguishing between red and green lights at an ordinarydistance. He was accordingly discharged from his office,as were many other pilots, who were found to be similarlyaffected. In re :.ly to Mr. Carter, he said that wood-engravingoften ruus in families, but sometimes one of the family is awater-colour artist.-The PRESIDENT remarked that a personwith artistic aptitude, but colour-blind, would naturallydevote himself to etching or engraving.-Dr. BRAILEYreplied, the substance of his remarks being given above.The Society then adjourned.

Reviews and Notices of Books.Fotp to Use the Forceps. By H. G. LANDIS, M.D.

New York : J. B. Treat.

THIS little work is divided into two parts. The firsttreats of the anatomy of the pelvis and the mechanismof labour, the second of the forceps and its application.The pelvis is described as consisting of two canals partiallyseparated at the inlet, but identical at the outlet. " Thesecanals converge from above downwards, and are mutuallycurved from before backwards. Their direction is thereforesomewhat spiral. The calibre of each canal is that of thefcetal head, therefore the head may descend in either canal,and will follow a spiral course in so doing." In accordancewith this view of the pelvis the mechanism of labour is

briefly explained as well as the principles which should

guide us in the application and use of the forceps. Theauthor recommends the use of the long forceps, but in theirintroduction and application regard is had to the head andnot to the pelvis, for the blades should grasp the head in thebiparietal diameter. The author is opposed to the employ-ment of the so-called leverage movement to effect delivery,and employs traction only, and this he applies after amethod of his own. He disapproves of the manner usuallyrecommended in text-books of making traction. He main-tains that pulling on the handles of the forceps dragsthe head not in the axis of the pelvis, but

against the symphysis pubis. In order to avoid this,he recommends that the handles should be held byone hand, so as to grasp the head firmly, and thatthe other hand should be "placed so that the ball of thethumb comes over the lock, while the index-finger rests uponthe upper arm of one blade, and the middle finger upon theother. Now, while the right hand holds the handles almostat rest, the fingers of the left push the blades so as to movethem and the contained head downwards, backwards, and alittle to the left of the median line. Secondly, while thefingers are pushing downwards in this way, we may alsomake use of them as a fulcrum, and by elevating the handlescause the blades to move in an opposite manner, but caremust be taken that the force thus applied by the right handis not enough to overbalance the downward pressure of the

left, else we will merely extend the head without propelling

it." The above will give some idea of the method of using the forceps recommended by the author. The work containsmuch that is original, and will repay a careful perusal.

The Natural History of Cranes. A inlonograph. By thelate EDWARD BLYTH, C.M.Z.S. Eularged, withnumerous Illustrations by W. B. TEGETMEIER, F.Z.S.Pp. 91. London: Horace Cox. 1881.

THIS prettily-illustrated work contains a zoologicalaccount of all the known species of cranes. It is foundedon a monograph by the late Mr. E. Blyth on the Grnids.but great additions have been made to it by Mr. Tegetmeier,which add much to its interest. The cranes, as a whole,are a very well-defined group, and some of them exhibit

intelligence of a kind that is rare amongst birds. Theirname (crane&mdash;grus&mdash;&ggr;&eacute;pavos&mdash;s&aacute;rr&aacute;s&mdash;k&aacute;rrunck, and the like;in different languages) is almost always onomatopmic, andindicative of the loud trumpeting sound they can emit.They are somewhat formidable animals when wounded,being able to transfix the walls of the abdomen with onestroke of their powerful and pointed bill, or to rip it openwith their recurved claws. It is stated that when the birdis wounded, the best way to avoid its attacks is to presentthe muzzle of the gun as it approaches. It will fix its billin the orifice, and may then be destroyed without danger,Several of the species migrate, the flock assuming a

V-shaped form and flying at a great height. The membersof the group are very widely distributed, being found every.where except in South America, the Malayan and PapuanArchipelago, and the scattered islands of the Pacific. Atone time they were common in the fenny counties of

England. They appear to be entirely vegetable feeders,Mr. Tegetmeier observes that old .fEsop’s fable of the storkbeing captured in the evil companionship of the cranes, andbeing condemned to death for thus associating with notoriousgrain-plunderers, indicates that he knew well enough thetwo kinds of birds, far better, indeed, than the renownedprince of mediaeval painters, who commits the zoologicalmistake of introducing cranes instead of storks into hisworld-famous cartoon of the miraculous draught of fishes.The cranes pair for life, and some, as the American whitecrane, propagate whilst still in the plumage of immaturity.The nest is built in swamps or lagoons, and most interestingaccounts are introduced from the notes of the late ColonelTickell of the love-making of the Grus antigone, and of Mr.Wolley upon their nesting, which he took infinite pains andtrouble to inspect. The Gruid&aelig; are divided into two groups,Balearica and Grus, the former being the crowned cranes ofAfrica; the latter include the Stanley or paradise crane; thedamoiselle crane, a beautiful specimen of which is now, orwas very recently, in the Zoological Gardens ; the wattledcrane ; the white-naped crane, common in Japan, and repre-sented on many of their ornaments; the Asiatic white

crane, and others. Mr. Tegetmeier places in an appendixsome observations he has made upon the convolutions of thetrachea in birds. This tube is remarkably developed in theGruidae, forming convolutions which are partly lodged ina groove of the keel, or sternum, and partly occupy thespace between the diverging limbs of the furculum. He is ofopinion, and he supplies many facts in support of his opinion,that the elongation of the windpipe, and the resulting twist-ing and convolution if it is much elongated, are connectedwith the deepness of the note and resonant character of thevoice. Several woodcuts illustrate the dissections ’_e hasmade. The work will be read with interest by everyzoologist and sportsman.

MR. ARTHUR FLINT, L.R.C.P., of Westgate-on-Sea.has been elected to the Board of Guardians and SanitaryCommittee of the Isle of Thanet Union.