196 



SCIENCE. 



[Vol. VI., No. 135. 



erate amount of attention might greatly modify these 

 conditions, and might do for the eyes what is done 

 by athletic games and exercises for the muscles. 



A still different explanation of the phenomenon is 

 given by G. B. Buckton jiV^a^wre, No. 801, p. 407). 

 The same amount of light entering the eyes of dif- 

 ferent individuals produces widely different effects, 

 according to health or age. A student becoming 

 accustomed to see objects from a short distance, will 

 permanently accommodate himself to a short focus, 

 and hence become short-sighted. Such modifications 

 can be conceived of as being hereditary, and long- 

 sight might be brought about in a race by the oppo- 

 site use of the eye. 



Apropos to this discussion, it may be well to notice 

 briefly a discussion upon near-sightedness, which was 

 started by Lord Eayleigh's article. The investigation 

 of the question of the increasing prevalence of short- 

 sight, which has recently been carried on in Germany, 

 has led to legislative restrictions in the schools. The 

 numerous statistics from the German schools have 

 shown that the proportion of short-sighted boys con- 

 tinually increases from form to form ; and from this 

 fact it has been argued that the continued use of the 

 eyes for the perception of near objects, is the essen- 

 tial, if not the only, factor in the production of short- 

 sight. This view is again supported by the statistics, 

 which allot the largest proportion of short-sighted 

 individuals to those branches of industry, or those 

 pursuits, which constantly call for near vision. In 

 this connection, Mr. George A. Berry {Nature, No. 

 800, p. 387) suggests that two points have been for- 

 gotten in arriving at such a conclusion. In the first 

 place, there is an undoubted tendency to grow short- 

 sighted with age alone, up to the period of cessation 

 of growth. This has been shown to be due to the 

 elongation of the antero-posterior axis of the eye, 

 and is no more a disease than is the attainment of 

 more than an average height by certain individuals. 

 It is merely a type; and, as such, is governed by the 

 laws of heredity. A small proportion of cases are, 

 however, due to disease; and these are as frequent 

 among the illiterate as the educated, and are not 

 hereditary. In many cases, people drift into literary 

 and similar pursuits because they are near-sighted, 

 and not well adapted for other occupations. Further, 

 as a man's circle of acquaintance is, for the most 

 part, amongst individuals having similar interests in 

 life, intermarriage in myoptic families must frequent- 

 ly occur, and would tend to perpetuate, and perhaps 

 increase, the defect. In savages, on the other hand, 

 where the great principle of survival of the fittest is 

 not frustrated to the same extent as among civilized 

 races, every thing would be against the perpetuation 

 of a myoptic type. 



CHEYNE'S OBSERVATIONS ON THE 

 CHOLERA MICROBE. 



In connection with the work of Van Ermengem 

 upon the cholera bacillus {Science, No. 133), that of 



Cheyne, recently published {British med. joiirn., 

 April 25-May 23, 1885), deserves attention. This 

 gives the results of his investigations at Paris during 

 the epidemic of cholera, and afterwards at his own 

 laboratory. In eight cases investigated, he found the 

 curved bacilli in larger or smaller numbers: in a 

 ninth case, supposed to be cholera, but turning out 

 not to be, no curved bacilli were found. He failed 

 to demonstrate these bacilli in the walls of the intes- 

 tines in almost all cases ; and, when he succeeded in 

 finding them at all, they were very indistinct. He 

 very justly observes, however, that Koch may suc- 

 ceed in such a demonstration where others fail; for 

 Koch's technique is unquestionably superior to that 

 of any other worker in this field. 



Having sent his slides and cultures to Koch, and 

 having the latter' s assurance that they were pure, 

 and made up of the curved bacillus of Asiatic chol- 

 era, Cheyne made various experiments with them 

 in culture-media of different kinds and at different 

 temperatures, the results of all of which were in 

 conformity with what was already known. In par- 

 ticular, he found no difficulty in repeating Koch's 

 observation, that drying rapidly destroys the vitality 

 of these organisms: 'in three hours they are com- 

 pletely dead.' 



His conclusions are, that the comma bacillus was 

 present, and generally in large numbers, in all the 

 cases of cholera which were examined ; and that he 

 has never met with the cholera bacillus except in 

 cholera, and that the other curved bacilli described 

 (Finkler and Prior's, Lewis's, and Dencke's or 

 Fliigge's), differ from it in important particu- 

 lars. 



Inoculation experiments were performed on seven- 

 teen guinea-pigs, with successful results in only two. 

 Two other animals died, but were not examined, 

 because destroyed. (We would suggest greater care 

 of his inoculated animals, for these misfortunes seem 

 to be but a repetition of those that happened in this 

 observer's work on tuberculosis ; see Practitioner, 

 April, 1883. ) 



The last part of Mr. Cheyne's article is devoted to 

 an able refutation of Klein's arguments against the 

 specific nature of the comma bacillus. He shows 

 the hasty work of this observer, which has led him to 

 conclusions so entirely at variance with those of 

 Koch and his supporters. He (Cheyne) thus sum- 

 marizes his opinion of the work of the English 

 cholera commission: " The two errors which, in my 

 opinion, lie at the root of the work of the English 

 cholera commission are, first, that, acting on the idea 

 that Koch diagnosed the cholera bacilli by the micro- 

 scope alone, they proceeded to investigate the matter 

 by microscopic examination; and, secondly, that, 

 seeing the stress which Dr. Koch laid on the cultiva- 

 tion appearances, they concluded that he meant to 

 say that the organism was pathogenic, because it 

 grows in a particular manner: and, therefore, they 

 naturally proceeded to inquire whether the appear- 

 ance of the cultivations, as compared with cultiva- 

 tions of other bacteria, could warrant this conclusion ; 

 and, of course, they found that it could not." 



