SCIENCE. 



[Vol. XXI. No. 539 



established, even without great accuracy of data, that among 

 civilized nations color-blindness is almost equally common. 



Second. Among uncivilized people Dr. Favre's results from 

 Algiers, already alluded to, show 414 examined, and only 2.6 

 per cent color-blind. 



Dr. Fox reports 161 young Indians in the United States tested, 

 and only 1.81 per cent are color-blind. 



These percentages, so low compared with those for civilized 

 people, suggested to us the thought that color-bindness may be a 

 product of civilization, and these have led to our own tests, here 

 reported. 



At the Haskel Institute, at Lawrence, Kansas, are several hun 

 dred Indians, representing many tribes. These we have recently 

 tested by Holmgren's method, with Berlin worsteds. 418 have 

 been examined — 285 males and 133 females — only three cases 

 of color-blindness exist, or only ^ of 1 per cent. These were 

 males, and all full-blooded Indians. The tribes were Pottawa- 

 tomie, Pawnee, and Cheyenne. Of these two had defective 

 color sense for red and one for green. 



The Indians werealmost evenly divided as full-bloods and half- 

 breeds. It seemed to us that the half-breeds showed more in- 

 stances of blunted color-sense than the full-bloods. This was 

 evidenced in more frequent and prolonged hesitation among 

 them in comparing the colors, than among the full-bloods. If 

 this be confirmed by more extended examinations, it would, in 

 conjunction with the low percentages obtained as above, be a 

 strong argument for the theory proposed by us, that defective 

 color vision is in some waj the product of civilization. To this 

 conclusion, our tests, at least, seem to point. The data are too 

 meagre at present to propose any explanation why defective 

 color-vision comes with civilization. It is not accidental that 

 nearly every case of color-blindness is for red, fewer for green, 

 and seldom one for violet. 



What is the meaning, that the defects are thus limited at 

 present, at least, to the lower end of the spectrum ? The Helm- 

 holtz- Young theory of color perception will locate the affection 

 in the layer of rods and cones responding to the first of the three 

 primary sensations of color. But why this special layer is, with 

 few exceptions, the only one affected, has at present no explana- 

 tion. Also why the percentage among females "is so small, has 

 no explanation. 



The law of heredity indicates increased sensitiveness in those 

 nerves which are subjected to special use through many genera- 

 tions. It seems reasonable to look foran explanation of the more 

 perfect color-sense iu females, to this fact, — but whether this 

 law of heredity will increase the percentage among males cannot 

 be foretold without an enormous increase of data. 



The theory here proposed is that defective color-sense is a 

 product of civilization with the use of tobacco as a possible fac- 

 tor. The non-use of tobacco would explain also the low percent- 

 age of color-blindness among females. This theory leads to the 

 thought of increase of color-blindness in males in the future gen- 

 erations. 



THE VERTICAL SCRIPT. 



BY W. H. METZLER, BOSTON, MASS 



I PRESUME that most of the people of this country were taught to 

 write the slanting script, according to a code of rules such as that 

 given by Spencer, DeGraff, and others. It would be interesting 

 to know what proportion have continued consciously or uncon- 

 sciously to observe those rules, and what proportion have for- 

 saken them for a position of body, pen, and book more suited for 

 rapidity and ease, and no doubt in many cases better from an 

 hygienic standpoint. 



Little obserfation will be required to convince us that there are 

 but few who observe the rules they were taught. 



Some years ago I had charge of about one hundred and twenty- 

 flve pupils in writing, who had been taught the slanting script 

 according to Spencer's rules. After using that method a short 

 time, I became convinced that the collapsed position which very 

 many assumed was due to the methods. When allowed to write 



as they pleased, about 5 per cent of them observed all the rules, 

 about 70 per cent observed part of them, but not all, and the re- 

 mainder apparently observed none of them. Those pupils placing 

 the book directly in front, with about an equal amount of both 

 forearms on the desk, sat most erect and wrote a script varung 

 but little from the vertical, and those turning the right side, 

 placing the right forearm on the desk parallel to its edge, sat least 

 erect. Observing this, and my own experience having taught 

 me that with paper directly in front I must sit more erect, could 

 write faster, and with a good deal more ease than with it at the 

 right, I directed the pupils to place their writing-books in front 

 of them, and found benetncial results follow in that the body was 

 kept more erect and the writing on the whole much improved. 

 At that time I had not heard of what is now known as the verti- 

 cal script. 



It, together with the many evils resulting from the methods 

 so commonly used in this country, was first prominently brought 

 to my mmd while attending a course of lectures given by Dr. 

 W. H. Burnham at Clark University in 1891-92. The substance 

 of which is contained in an invaluable paper published in the 

 Pedagogical Seminary/, Vol. II., No. 1. Dr. Burnham has made 

 a thorough study of the subject of school hygiene, and his paper 

 gives, besides a comprehensive bibliography, the opinions and 

 conclusions of the best writers and investigators of different 

 countries, and should be in the hands of all teachers and school 

 boards. 



The following are some of the rules given by Schubert for 

 writing the vertical script : — 



1. Straight-central position of the tablet or copy-book. 2. 

 Two-thirds of both forearms should rest on the desk in sym- 

 metrical positions, meeting at right-angles and forming an 

 angle of 45° with the edge of the desk. The elbows should 

 be about a hand's-breadth from the body. 3. The hand should 

 rest on the outer edge of the nail of the little finger. The index 

 finger should form a slightly convex bow. 4. The pen-holder 

 should be long and grasped not too near the pen. Its upper part 

 should not rest against the index finger, but on the middle of the 

 hand between the thumb and index finger, and should point 

 towards the elbow rather than towards the shoulder or breast. 5. 

 The arm as it moves toviard the right in writing should be moved 

 as a whole, so that all positions that it occupies will be parallel. 

 6. After each line the paper should be correspondingly raised, so 

 that a proper distance between the point of the pen and the edge 

 of the desk be preserved. 7. The lines should be short. 8. The 

 lines joining the eyes and the shoulders should be horizontal, and 

 the eyes from 30 to 35 centimetres from the paper. 



Since hearing the lectures and reading the paper, I have made 

 some observations to ascertain whether those placing the book 

 directly in front of them sit more erect than those who place it at 

 the right, and though I did not find many who used the straight- 

 central position, yet I found that a larger per cent of those placing 

 the book in front sit erect than of those placing it at the right. 



Since so many evils are due to poor methods in writing, it would 

 seem that the subject should receive far more attention than has 

 heretofore been given to it, and the vertical script be given a 

 thorough test at least. The fact that no two hand-writings, like 

 no two faces, are exactly alike would indicate that, after a few 

 general instructions to secure a healthful position of the body, no 

 complex set of rules should be given. Each person will then de- 

 velop that particular hand-writing most suited to him. 



DISINFECTANTS AND DISINFECTION. 



BT HAVID BEVAN, M.D., PHILADELPHIA, PA. 



The question of disinfectants and disinfection has come to be 

 of as great practical importance as it is of scientific interest. 

 The term disinfectant is by the laity, and to some extent by the 

 medical profession, grossly misused in being considered as syn- 

 onymous with antiseptic and deodorant, since science has so abJy 

 demonstrated the nature of the contagium in infectious and con- 

 tagious diseases, only such agents as are capable of destrojing 



