On the Mechanism by Which the First Sound of the Heart Is Produced
Richard Quain
1897
Proceedings of the Royal Society of London
illum inated surface. H aving experim ented w ith the extinction of light at o th er p a rts of th e retin a, he finds th a t it obeys the same law. Since a large and a sm all area having th e same actual illum i nation appear to be of different brightness, an investigation was m ade of the relative lum inosities of the two, and it was found th a t the two were connected by a very simple law. T he reduction of the intensity of a coloured ray to extinguish all colour was next m easured w ith
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... s of different dimensions, an d it was shown th a t again the intensity of the reduced lig h t was connected with the size of th e spot by a simple expression sim ilar to th a t of th e extinction of all lig h t, b u t the exponential coefficient differed, indicating th a t lig h t and colour were not connected together in th e m anner w hich m ig h t he expected. The au th o r th en deals w ith th e question of colour fields, and finds th a t all colour fields are of th e same form, the extent depending solely on the illum ination and the area of th e surface the im age of which falls on th e retina. H e finds th a t th ere is a connection between th e in ten sity of the colour and th e extent of the field which can be expressed by a form ula, as also can the connection between the size of th e spot of illum inated surface and the extent of field. H e gives the curves of illum ination for equal colour fields, and the curves of ex ten t of field for every colour in the prism atic spectrum . Finally he makes an investigation into the relative sensitiveness to light of various points in the retina, and shows th a t there are " iso-lumes " or fields of equal sensitiveness w hich appear to be of the same form as th e colour fields. He points out th a t there are difficulties in reconciling these results with either the Y oung or H ering theory of colour vision, and suggests a modification in the accepted theory of lig h t and colour which may explain the connection between th e two. * 'Text-book of Physiology,' 6tli Ed. (London, 1893), p. 239. + I have to acknowledge with thanks the assistance rendered me in arranging my notes of this memoir by my valued friend, Dr. Mitchell Bruce, during my recent severe indisposition.
doi:10.1098/rspl.1897.0045
fatcat:k4ackwqf6rf7fp7stz3jo5ubmm