July 8, 1909] 



NATURE 



49 



Frimley is a very different thing from the treatment carried 

 on in the early days of sanatoria. Patients are no longer 

 stuffed and rested indiscriminately. They are given 

 work, rest, and food on a carefully graduated system ; 

 they are taught how to treat themselves — what to do and 

 what to avoid. The sanatorium treatment, however, deals 

 with but a small proportion of the cases ; tuberculosis 

 must be tackled on a much more extensive scale. Calmette 

 in Lille and Philip in Edinburgh, seeing the importance 

 of bringing the treatment of tuberculosis to the working 

 classes and even the very poor, have organised what is 

 now known as the dispensary system, in which are com- 

 bined an intelligence department, an ambulance service, a 

 training school, an out-patient and in-patient hospital 

 service, and a sanatorium department. \\\ Edinburgh the 

 result has been a fall in the death-rate beyond that of 

 other cities equally or more favourably situated, except in 

 that they have not been provided with this well-organised 

 system. 



It is recognised that prevention of tuberculosis is 

 certainly more important than its cure, and all interested 

 in this question must realise what enormous impetus 

 has been given to the whole movement by the energetic 

 action taken by the President of the Local Government 

 Board. His keen interest in the Milk Bill, in the Wash- 

 ington Congress on Tuberculosis, and in the Whitechapel 

 Exhibition, his grasp of principles and the wealth of 

 detail contained in his opening address at that exhibition, 

 gave evidence of complete conviction and determination to 

 act up to his conviction. All this marks a great advance 

 in the public treatment of the question in this country. 

 Medical men have long suspected that tuberculous milk 

 was a prolific cause of abdominal consumption amongst 

 their little patients. They have known how readily delicate 

 children recovering from measles, whooping cough, in- 

 flammation of the lungs, and similar conditions, have 

 been infected, sometimes from tuberculous patients, at 

 other times, however, under conditions where infec- 

 tion from the human subject appeared to be impossible, 

 and they now welcome with enthusiasm any legis- 

 lation that will render impossible the spread of 

 tuberculosis by the milk from infected cattle. Medical 

 officers of health, aware of the insanitary conditions under 

 which a large proportion of the population, not only urban, 

 but rural, live, hail with satisfaction the idea that in 

 any well-considered action they may take they will now, 

 not only be commended, but helped. The National 

 Association for the Prevention of Consumption has done 

 well, not only to follow Ireland and .\merica, but to 

 improve upon the methods adopted in those two countries. 

 Nothing but good can be the outcome of this movement, 

 and we hope that the seventy thousand visitors to the 

 Whitechapel Art Gallery will be followed by hundreds of 

 thousands, who will have the opportunity of seeing this 

 or a similar exhibition at the *' White City " or on 

 its tour through the large and populous centres of England, 

 and perhaps even of Scotland. 



VISION IN RELATION TO HEREDITY 



AND ENVIRONMENT.' 



"T^HE Francis Gallon Eugenics Laboratory at University 

 •^ College, London, has already done much valuable 

 work in many directions under the supervision of Prof. 

 Karl Pearson. With the assistance of Miss Harrington, a 

 useful inquiry has been made into the question of the 

 inheritance of vision and the relative influence of heredity 

 and environment on sight. The paper is a mathematical 

 investigation of statistics culled from a variety of sources. 

 Of these, two communications by Dr. Adolf Stciger, of 

 Zurich, on the corneal curvature, and the report on 1400 

 school children issued by the Edinburgh Charity Organisa- 

 tion Society, afford the best material. Other contributory 

 material of less value is taken from reports on the refrac- 

 tion of London elementary-school children by Dr. A. 

 Hugh Thompson and the Education Committee of the 



1 Univer^ityof London. Francis Galton Laboratory for National Eugenics. 

 Eusenics Laboratory Memoirs. V. A First Study of the Inheritance of 

 Vision and of the Relative Influence of Heredity and Enviromient on 

 Sight. By Amy Barrin^ton and Karl Pearson, F.R.S. Pp.61. (London: 

 Dulau and Co., igog.) Price 4J. 



NO. 2071, VOL. 81] 



London County Council, and on the eyesight of 500 

 Glasgow school children by Dr. Rowan. Throughout, the 

 difhculty which specially besets such statistical investiga- 

 tions is present in the fact that all the material is intensely 

 selected. There is no means of supplementing it by a 

 knowledge of the distribution of astigmatism and other 

 errors of retraction in the community at large. Thus, in 

 dealing with percentage statistics of the heredity factor 

 in myopia, the authors say that " the distribution of 

 parents of the normal and the proportion of myopes to 

 the normal in the general population (or at any rate in 

 the ' universe under discussion ') must be found before any 

 appreciation of the effect of heredity can be made." 



The first moot point which arises in dealing with the 

 inheritance of refraction concerns the determination of the 

 unit to be used to obtain a quantitative scale. It is now 

 customary to measure the refraction in terms of the :e- 

 fractive power of the correcting lens instead of, as 

 formerly, in terms of its focal distance. When the varia- 

 tions of the mean values in the population are small com- 

 pared with the mean value in the individuals undor 

 discussion, it matters little which unit is adopted. This 

 is true of corneal refraction (3 per cent.), but untrue of 

 corneal astigmatism (75 per cent.). The difficulty is over- 

 come by using, whenever possible, the method of con- 

 tingency, fundamentally, or for purposes of control. 



Investigation of the inheritance of corneal astigmatism 

 leads to the conclusion that it is certainly inherited, as 

 evidenced by minimum limits of 0-3 to the parental and 

 of 0-4 to the fraternal coefficients, but the material is 

 neither sufficient nor sufficiently classified to determine 

 with any degree of certainty the accurate value of the 

 inheritance coefficients. The authors point out that 

 " there is a snlendid field for a man who will measure 

 the corneal astigmatism in a non-selected poDuiation. '' As 

 this would be an easy and accurate task with the 

 ophthalmometer there ought to be no difficulty in getting 

 it carried out. Investigation of corneal refraction shows 

 that it is inherited at the same rate as other physical 

 characters in man. In dealing with the inter-relations of 

 refraction, keenness of vision, and ago, the results show 

 how much more influence myopia has on visual acuity 

 than hvpermetropia, and that refraction defects contribute 

 more than half the abnormality of keenness of vision. 

 They further show that there is not the least doubt of 

 a sensible relationship of age to each of the several cate- 

 gories of eye defect. It is probable that a great deal of 

 hvpermetropia, hypermetropic and mixed astigmatism dis- 

 appears, probably owing to growth, between six and ten, 

 thus swelling the number of emmetropic eyes, but that 

 after this age there is not sufficient evidence to say -whether 

 these categories vary or not. Myopia and myopic astig- 

 matism increase throughout, but this increase does not 

 balance the total gain due to rectification by growth ; it 

 may be caused by continued action of some environmental 

 factor, or by a growth factor. 



The general conclusions derived from the slender data of 

 this first study are as follows : — There is no .evidence what- 

 ever that overcrowded, poverty-stricken homes, or physi- 

 cally ill-conditioned or immoral parentages are markedly 

 detrimental to the children's eyesight. There is _ no 

 sufficient evidence that school environment has a deleterious 

 effect on the eyesight of children. Though changes of 

 vision occur during school years, they are phases of one 

 law of growth, a passage from hvpermetropia to 

 emmetropia and myopia of the eyes of " unstable stocks.' 

 There is ample evidence that refraction and keenness of 

 vision are inherited characters, and that the degree of 

 correlation between the eyesight of pairs of relatives is 

 of a wholly different order to the correlation of eyesight 

 with home' environment. Intelligence as judged by the 

 teacher is correlated with vision in only a moderate manner 

 (p. 16). We scarcely think that the data justify so strongly 

 worded an ex cathedra statement as that made by the 

 authors in conclusion :—" The first thing is good stock, 

 and the second thing is good stock, and the_ third thing 

 is good stock, and when you have paid attention to_ these 

 three things fit environment will keep your material^ in 

 good condition. No environmental or educational grind- 

 stone is of service unless the tool to be ground is of 

 genuine steel — of tough race and tempered stock." 



