August 31, 1916] 



NATURE 



000 



by the circular portion of the ciliary muscle and made 

 to bulge in the centre explains all the clinical pheno- 

 mena, which the old theor)* (Helmholt's) failed to do. 

 The aberration which the central bulging would cause 

 at the margin of the lens is masked by the contraction 

 of the pupil, which always accompanies normal 

 accommodation ; thus the accommodative power de- 

 pends rather on the "squeezability" of the lens than 

 the power of the muscle. Now this " squeezabilitj' " 

 of the lens becomes less as the lens tissue becomes 

 firmer. I have known in a young child the accom- 

 modative power to be as much as 20 D., whereas it 

 is rare to find anyone above fortj'-five with an accom- 

 modative power higher than 4 or 5 D. Donders gave 

 us a diagram showing the gradual loss of accommo- 

 dative power through age, i.e. through the sclerosing 

 of the lens, but he only examined 150 cases, and in- 

 cluded in these some latent hypermetropes, so that he 

 reckoned the accommodative power per age lower than 

 it really is. 



The diagram (Fig. i) was prepared by me from 1200 

 cases, all of which were first made normal by correct- 

 ing their defects. Donders's mean line is marked, and 

 it is seen that it coincides practically with my mini- 

 mum line from the age of thirt}-. From my table the 

 presbyopic point may be said to be arrived at between 

 ages fort\--five and forty-eight ; in other words, the 

 emmetrope, or those made emmetropic by correction, 

 must at that age have increased help for near work. 



In the above table made from my diagrams there 

 is seen to be a great difference between the maximum 

 and minimum. What is the cause of this difference? 

 If a person has more accommodative power than the 

 average it means that he is younger than his years, 

 and if less, older. 



Among the many causes of premature seriilit)', which 

 a lessened accommodative power implies, the follow- 

 ing are the chief : — 



(i) Alimentary Toxaemia. — ^As amply shown by Sir 

 William Arbuthnot Lane. In these cases I have found 

 the lens to be a very delicate index. 



(2) Eyestrain. 



(3) Worry, Anxiety, Sorroiv, and Overwork. — ^This 

 war has hastened the onset of presbyopia, and in- 

 creased it rapidly in those already presbyopic, through- 

 out England, and probably throughout Europe. The 

 only preventive treatment is peace, but until that comes 

 we should conserve all the nervous energy we have 

 and not waste it. 



Intestinal toxaemia should be removed by the surgeon 

 or physician. Eyestrain should be prevented; if there 

 is any defect besides the presbyopia (and it must be 

 remembered that simple presbyopia is ver^' uncommon, 

 only about i per cent, of presbyopes) it must be 

 corrected, and the invisible bifocal glasses, which cor- 

 rect the distant vision in the upper portion and the 

 reading in the lower, give the best result. If two 



NO. 2444, VOL. 97] 



separate glasses are worn they are not changed when 

 they should be. The presbyopic period is just that timt 

 of life when it is most important to conserve all pos- 

 sible nerve energy. Responsibilities, worries, and 

 anxieties are probably at their maximum, and we have 

 not yet reached the callousness of old age ! 



Finally, for our own sakes and also for those around 

 us, we should not make the most of our troubles : 

 we should not go out to meet them, nor let "to-day's 

 strength bear to-morrow's loads." 



UNIVERSITY AND EDUCATIONAL 



INTELLIGENCE. 



The Board of Education has issued a circular (961) 

 stating that with a few alterations the Regulations for 

 Technical Schools, etc., in England and Wales (Cd. 

 7996) will continue in force for the school year 1916-17. 

 The special regulations for grants in aid of instruc- 

 tion for men serving with the colours are withdrawn, 

 as it appears from the returns of the work done during 

 the past winter that there is now little demand in 

 camp for classes of an educational character. 



The Weardale Lead Company is establishing two min- 

 ing scholarships, each of the annual value of 6cJ., in 

 connection respectively with the Royal School of Mines 

 and Armstrong College, Newcastle-upon-Tyne, with 

 the object of combining university- training with 

 a year's practical work calculated to advance a student 

 in the knowledge of mining engineering. The scholar- 

 ships are to be known as the " Richardson " and the 

 "Cameron," after two directors of the company. 



The first award of the annual prize of 40Z. founded 

 bv the Earl of Cromer, and administered by the 

 British Academy, for the best essay on any subject con- 

 nected with the language, historv', art, literature, or 

 philosophy of ancient Greece, will be made before the 

 end of 19 1 7. The competition is open to all British 

 subjects under the age of twent\-six years on October i, 

 19 17. Intending competitors must send the title of 

 their proposed essay to the Secretary of the British 

 Academv, Burlington House, Piccadilly, on pr before 

 December i, 1916. The essays on approved subjects 

 must reach the Academy by, at latest, October i, 1917- 



The current issue of the Reading University Col- 

 lege Review is concerned almost exclusively \\-ith the 

 affairs of the college. It includes the sixth revised 

 list of present members of the staff, past and present 

 students, and present servants of the college who are 

 serving with the Forces or in the French Army. The 

 numerous notes which begin the re\'iew ser\-e as an 

 excellent record of the various developments in the 

 activities of the college. Among these, the extension 

 of domestic training may be mentioned. A scheme has 

 been sanctioned for a diploma course in domestic 

 subjects extending over two years, and for a certificate 

 course extending over one year. The aim of these 

 courses is to train girls of good secondarv' education 

 to manage an institution, household, or home with 

 practical efficiency and intelligence. Instruction in 

 poultn.'-keeping has been inaugurated, and the work 

 of the department of horticulture is being extended. 



SOCIETIES AND ACADEMIES. 

 Paris. 

 Academy of Sciences, August 14. — M. Paul Appell in 

 the chair. — C. Richet : The conditions which influence 

 the average monthly deviation of the birth-rate. In 

 countries with a high birth-rate (more than 350 per 

 10,000) the mean monthly deviation of the birth-rate 



