8 



arrive at a knowledge of the coustitixtion of the 

 sun and stars. A number of coloured objects were 

 she^TU in coloured light, and revealed remarkable 

 changes in their colour when the illumination was 

 altered. The colours of bodies were due, the 

 lecturer explained, to the vibration either of their 

 separate particles or to portions of these. Models 

 and plans of the structure of the complex mole- 

 cules of the dye substances were shown. A very 

 slight change indeed, either of composition or 

 arrangement, was shown to make a great difference 

 in the colour of the dye, and hence some idea could 



be formed of the enormous number of possible 

 shades. The basis of these dyes is almost invari- 

 ably aniline, a product of coal tar. The method 

 was shown of fixing the dye by means of a mordant, 

 and also the way in which bleaching is carried out. 

 The lecturer concluded by exhibiting a great 

 variety of coloured fabrics kindly provided by the 

 chemist of the Berlin Aniline Dye Company. 



Mr. Harvey, in thanking the lecturer, referred 

 to the difficulties experienced by the pioneers in 

 the subject, and to the fact that the initial dis- 

 covery was, like so many others, a pure accident. 



THE EVOLUTION OF THE HUMAN EYE." 

 By a. lander, Esq., F.S.M.C. 



The last meeting for the session took pUce on 

 March 23 in the Reference Library at the I-eaney 

 Institute, Canterbury. Mr. A. Lander, hon. secre- 

 tary of the society, was the speaker, and his sub- 

 ject was the "Evolution of the Human Eye." As 

 is well known, Mr. Lander is a keen student of 

 this subject and the members were looking forward 

 to an interesting lecture, and in this they were not 

 disappointed. The speaker illustrated his remarks 

 with a series of microscopic slides, which were 

 capitally exhibited by means of his lantern micro- 

 scope, in fact, Mr. S. Harvey, the President of the 

 Society, remarked at the close that they had had 

 a magnificent display. He had seen, he said, a 

 great many microscope displays, but never one to 

 equal that (applause). 



Mr. Lander explained that he feared his lecture 

 was souietbing of a makeshift ("No"), but two of 

 their members who had promised to give lectures 

 had had a breakdown and were unable to assist in 

 filling up the programme, and therefore he would 

 do his best to fill the gap. He did not propose 

 to give them the v.hole history of the evolution of 

 the human eye, that would take too long, but he 

 intended to run briefly through the various 

 stages. He designated sight as the most precious 

 of the senses. It was the only sense that brought 

 one into touch with the infinite. The eye was 

 not always as perfect as it was in the human 

 brain. In some of the lower creatures it w^is very 

 primitive. Professor Darwin and others had 

 discovered that plants had eyes. That might 

 seem a very preposterous thing to say, but they 

 ■would all acknowledge that plants had their 

 sense of feeling. All knew that if a plant was 

 turned away from the light it would turn itself, 

 if possible, back again. If they went a little 

 further they would set' tliere must be some method 

 by which the plants could tell where the light 

 was. Quito recently they had found out that 

 spread over the leaves were little bulging cells, 

 which appeared to concentrate the light or focus 



it upon the nucleus of the cell. If these little 

 bulging cells were removed, the plant no longer 

 turned to the light, and photographs could be taken 

 by means of these little lenses as with the eyes of 

 insects. Passing on to the lower types of creatures 

 Mr. Lander traced the gradual develoi>ment of 

 the organ of sight until it reached its highest 

 form in the human being. Among the slides 

 exhibited was that of a photograph taken through 

 the eye of an ordinary house fiy, using that organ 

 as a lens. The photograph was one of the late 

 Queen Victoria, and the plate contained a 

 large number of small reproductions, instead of 

 one large one. In dealing with the phenomena 

 of the colour of the human eye, Mr. Lander stated 

 that this was governed by what was known as 

 Mendel's law of heredity, and knowing what 

 was the colour of the parents' eyes, it was possible 

 to tell what colour the eyes of their children 

 would be. Long sight, explained Mr. Lander, 

 was caused by a defect in the shape of the eye. 

 If a person's eye was too flattened — not globular 

 in shape — he would be long sighted. If, on the 

 other hand, the eye was too long the person would 

 sutler from short-sightedness. Colour blindness, 

 he said, had lately been discovered to be hereditary. 

 The first generation would, however, have normal 

 vision, but the daughters' sons would be partially 

 colour blind. In Canterbury there were probably 

 between oOO and 600 persons who were more or 

 less colour blind. 



At the close of the lectiire Mr. Roberts, science 

 master of St. Edmund's College, gave a demonstra- 

 tion of an apparatus which he had constructed 

 for the purpose of making slide rules. With the 

 aid of the machine it was possible to obtain the 

 greatest accuracy even to the minutest fraction 

 oi an inch, and at the close of the demonstration 

 Mr. Harvey complimented Mr. Roberts on his 

 invention. 



'Ihe meeting concluded with a very hearty vote 

 of thanks to Mr. Lander for his interesting lecture, 

 Mr. Harvey putting forward the motion. 



