390 



SCIENCE. 



[N.S. Vol. XXIII. No. 584. 



of the Marsh apparatus, slightly modified for 

 greater convenience. The original apparatus 

 is described in the February number of the 

 Journal of the American Chemical Society. 

 By means of an improved method of distilla- 

 tion and concentration, and this apparatus. 

 Bishop detected one part of arsenic in a bil- 

 lion parts of sulphuric acid. 



C. E. Waters, 



Secretary. 



THE VERMONT BOTANICAL CLUB. 



The eleventh annual meeting of the Ver- 

 mont Botanical Club was held at the Univer- 

 sity of Vermont, January lY and 18. Some 

 twenty papers were presented, including 

 ' Recollections of the Botanical Work of 

 Joseph Torrey,' by Miss Mary Torrey ; * The 

 Thorn-apples of Vermont,' by W. W. Eggles- 

 ton ; ' The Flora of Hawaii,' by Professor G. 

 H. Perkins; ' The Finding of Aspidium Filix- 

 Mas in Vermont,' by Miss N. Darling; 

 ' Reminiscences,' by Cyrus G. Pringle ; ' Va- 

 riations Among Violets,' by Ezra Brainerd. 



It was decided to begin the publication of 

 an annual bulletin of which the first number 

 will appear this spring. 'The next field meet- 

 ing will occur about July first on Mt. Mans- 

 field; the next annual winter meeting at St. 

 Johnsbury. The officers were reelected as 

 follows : 



President — Ezra Brainerd, Middlebury College. 



Vice-President — C. G. Pringle, University of 

 Vermont. 



Secretary— L. R. Jones, University of Vermont. 



Treasurer — Mrs. N. F. Flynn, Burlington. 



Executive Committee — Dr. H. H. Swift, Mrs. E. 

 B. Davenport, Miss I. M. Paddock. 



L. R. Jones, 

 Secretary. 



DISCUSSION AND CORRESPONDENCE. 



EYE ANOMALIES. 



I HAVE recently found that my eyes are 

 abnormal in a way which is quite new to me, 

 and which seems to be outside of the usual 

 group of symptoms utilized by the physicians. 

 The effect is interesting and I venture to ask 

 whether any reader of Science can enlighten 

 me. Both eyes are near-sighted but free from 

 astigmatism. 



1. In the first place I see double images 

 with each eye. A black circle, about four 

 centimeters in diameter, regarded from a dis- 

 tance of six meters with one eye, appears aa 

 two circles with their centers on a line about 

 45 degrees to the horizontal, intersecting so 

 that the center of one lies nearly on the cir- 

 cumference of the other. The images are 

 about equally strong, naturally quite black 

 where they intersect and there seems to be a 

 dot at the center of each. There is some 

 vague color. With the left eye there is a 

 tendency to repeat this phenomenon sym- 

 metrically; i. e., the circles lie with their 

 centers at an angle of 135 degrees to the hori- 

 zontal, but they are much further apart, often 

 tangent to each other. This eye is more near- 

 sighted. Moreover, when the eye is under the 

 influence of belladonna (or even at other 

 times) there may be two or more pairs of 

 images, a strong pair at 135 degrees outside 

 each other, and a weaker pair at about 45 

 degrees tangent to these; or the figures may 

 be even more complicated. All circles have 

 central dots. With appropriate glasses the 

 images of both eyes become nearly clear. No 

 explanation which has occurred to me (reflec- 

 tion from non-centered systems, split-lens 

 effect, polarization) exactly meets these cases. 



2. A second phenomenon which may hold 

 the key to the preceding is the following. If 

 at night I look at a distant electric light (100 

 feet off, or more) with the left eye and with- 

 out glasses I see the usual patch of light of 

 the near-sighted eye. This patch, however, is 

 not a uniformly bright disc about one de- 

 gree in angular diameter, but contains an 

 accurately drawn circle in black of a diameter 

 somewhat less than one third that of the disc 

 and placed a little above the center to the 

 right. There is no appreciable color effect 

 or successive annuli. The circles, though 

 scarcely visible within fifty feet, from the 

 light naturally increase in size with the dis- 

 tance of the source. There is no doubt that 

 with an appropriate Wollaston prism (depart- 

 ing somewhat from the ophthalmometer) they 

 could be used for the measurement of this dis- 

 tance. In explanation of these phenomena it 

 seems to me that a globule of relatively low 



