June 13, 1918] 



NATURE 



295 



n iating to the supply of electricity be transferred. It 

 i(>commends that the existing system of generating 

 • iectricity for small areas be abolished. One of the 

 t'lrst duties of the Electricity Commissioners would be 

 it) divide the country into districts technically suitable 

 tor the generation and distribution of electricity. In 

 each district an Electricity Board is to be set up, 

 which will purchase all the generating stations in it. 

 These Electricity Boards are to be financed in whole or 

 in part with Government assistance, and are to make 

 no divisible profits. The Committee laudably strives 

 to conciliate those authorities and engineers who are 

 adversely affected by its proposals. It claims, how- 

 ever, extended powers for the use of overhead wires, 

 wayleaves, and the acquisition of water rights. From 

 the practical point of view the proposals are good, and 

 their adoption, provided that they could be smoothly 

 carried out, would be greatly in the national interests. 

 We hope that Parliament will give to these proposals 

 its most seriou§ consideration. 



THE EDUCATION BILL. 

 'T'HE debate on clause lo, the rnost important feature 



-*■ of the Education Bill, was resumed in Committee 

 of the whole House on Wednesday, June 5, and con- 

 tinued on June 10 and 11. Sir H. Hibbert submitted, 

 at the instance of many Lancashire Members, an 

 alternative scheme to that of the Bill, whereby, at the 

 option of the local authority, half-time between four- 

 teen and sixteen years of age and thenceforward no 

 compulsory scheme of- continued education might be 

 substituted for the proposal in the Bill to require 

 between the ages of fourteen and eighteen a maxi- 

 inum of 320 hours in each year to be included within 

 the ordinary working hours. Mr. Fisher opposed the 

 amendment on the ground that it could not be made 

 mandatory over the whole country, that it would 

 seriously reduce wages, introduce confusion into 

 administration, and would practically double the 

 demand for teachers and for school accommodation. 

 To the great disappointment of many friends of the 

 measure, and especially of this important and vital 

 feature of it, Mr. Fisher, in response to representa- 

 tions not only on behalf of the textile industry, but 

 also in respect of agriculture and of coal-mining, sub- 

 mitted amendments to section i. of clause 10 reduc- 

 ing the compulsory hours in each of the four years 

 from 320 to 280, if the local authority so resolve, 

 and providing that the obligation to attend continua- 

 tion schools shall not, within the period of seven years 

 from the appointed day on which the provisions of 

 clause 10 (i.) come into force, apply to young persons 

 between the ages of sixteen and eighteen. The 

 Lancashire Members thereupon withdrew their o'ppo- 

 sition, and Mr. Fisher's amendments were adopted, 

 together with an amendment leaving the local 

 authority free to deal with the times and seasons best 

 suited to the circumstances of each locality. Difficul- 

 ties of buildings, equipment, and the supply of 

 teachers had doubtless something to do with this 

 decision, but the great advantage gained by the con- 

 rfssion is permanently to secure the educational over- 



'^ht of the adolescent until he reaches the age of 

 > ighteon. On Monday Mr. Fisher accepted an amend- 

 ment by which it was agreed to establish a national 

 scheme for training boys who desire to enter the 

 mercantile marine. Sir' Philip Magnus moved to 

 amend subsection 2 in such a way that the recogni- 

 tion of a school as efficient by a' British university, 

 equally with such recognition by the Board of Educa- 

 tion, should make full-time attendance in that school 

 up to the age of sixteen years a ground of exemption 

 from the obligation to attend continuation schools. 



NO. 2537, VOL. lOl] 



After discussion the amendment was withdrawn, and 

 Mr. Fisher ag^-eed to substitute for the words "under 

 arrangements approved by the Board of Education" 

 the words "under regulations made by the inspecting 

 body after consultation with the Board of Education." 

 It was suggested in the discussion on Tuesday that 

 pressure might be brought to bear upon young persons 

 to attend continuation schools at or in connection 

 with their place of employment. An amendment was 

 afterwards accepted against any such compulsion by 

 a local authority without the consent of the young 

 person or his parents. Clause 10 was finally agreed to 

 as amended. 



LIGHT AND VISIONA 



'X'HE phenomena which take place between the 



-■■ incidence of light on the cornea and the mental 



appreciation of the fact may conveniently be divided 



into three stages : — 



(i) The production of an image on the retina by 

 means of the dioptric system of the eye. This is 

 purely a physical question, and has been very com- 

 pletely worked out. The only component of a physio- 

 logical nature is the mechanism of accommodation, 

 by which the curvature of the lens is changed in 

 order to vary the focal length of the system. It 

 would appear ihat the muscular mechanism here in- 

 volved is liable to fatigue, and doubtless plays its 

 part in the choice of appropriate methods of illumina- 

 tion, as in the tests used by Ferree.^ It will also be 

 plain that insufficient illumination requires more exact 

 and tiring accurate adjustment of focus. 



(2) When light arrives at the particular layer of 

 the retina known as that of the rods and cones, it 

 excites a photo-chemical change of some kind, which 

 in its turn acts upon the terminations of the optic 

 nerve-fibres and sends along these fibres a series of 

 disturbances which we call nerve impulses. 



(3) Arriving at the brain, these impulses are dis- 

 tributed to a complex system of centres composed of 

 nerve-cells, where processes occur associated, in some 

 mysterious way, with the conscious perception of light 

 and illuminated objects. 



We naturally ask the question : — What kind of 

 sensation do we experience if the optic nerve is 

 stimulated in other ways, as can be done by means of 

 sufficiently powerful agents? The answer is that 

 whatever be the way in which the optic nerve is 

 stimulated, the sensation is one of light. This state- 

 ment applies, altering light for sound, taste, etc., to 

 all the nerves of special sense, and is commonly 

 known as Miiller's law. In point of fact, it had been 

 formulated by Sir Chas. Bell at an earlier date, though 

 perhaps in not so complete a form. The sensation, 

 then, is an affair of the brain, the " cerebral 

 analysers," as Pavlov calls them, and provided that 

 this part of the brain is set into activity, it matters 

 not by what means, the sensation is the same. This 

 again applies to all the special senses. What, then, 

 is the function of the elaborate structure at the peri- 

 pheral end of the nerve? Such organs are known in 

 general as "receptors," and their function may be 

 grasped if we try to stimulate the optic nerve by 

 throwing a beam of light upon it. Nothing happens 

 at all, because the nerve-fibres are not responsive to 

 light energy. Some sort of mechanism that is 

 affeded by this form of energy must be provided, and 

 is to be found in the rod and cone layer of the retina. 



But what is passing along the optic nerve when a 

 light sensation is experienced is identical with that 



1 Abridged from a paper read at themeelin(f of the Society of Illuminating 

 Engineers on April i6 by Prof. W. M. B.iyHss, F.R.S. 



Si Trans. Illumin. Engineer. Soc. (U.S.A.), vol. viii., p. 40, and Ferree 

 and Rand, iit'i/. 



