Microscopical Society. 1619 



ing to a previous paper on the same subject, read before the Society 

 in March last, in which he described certain characters peculiar to 

 the bones of each of the four great classes of the vertebrate kingdom, 

 by which a bone of each class could be easily distinguished, and 

 after pointing out the importance of the knowledge of this sub- 

 ject to the palaeontologists and geologists, in enabling them to de- 

 termine the nature of any fossil fragment of bone, however minute, 

 he went on to state, that he had ascertained that the cells of the bone 

 bore a certain relation in point of size, to that of the blood-discs ; 

 thus for instance, the blood-discs were found to be largest in reptiles, 

 smallest in birds and Mammalia, and were in fishes of an intermediate 

 size ; and he had discovered that the bone-cells followed the same 

 law. In the present paper, Mr. Quekett states the result of his ex- 

 amination of the structure of the bone of the perennibranchiate rep- 

 tiles, viz. — the Syren, Proteus, and Axolotl, which have the largest 

 blood-discs of all the Vertebrata, and he found that in them the bone- 

 cells were the largest also, which fully bore out, and confirmed his 

 former statement. Diagrams were exhibited which represented the 

 bone-cells in the human subject, the ostrich, turtle, Syren, and 

 Lepidosteus, when magnified by 453 diameters, by which means, 

 their characteristic differences were rendered very evident. 



A second paper by John King, Esq., of Ipswich, was read, on a 

 method by which all objects may be polarized under the Microscope. 

 The analyser consists of a double image placed over the eye-piece of 

 the instrument, a plate of selenite is then put upon the stage, the 

 edges of this field will then appear coloured, while the centre remains 

 colourless. Any object introduced into this field will exhibit the ef- 

 fects of polarized light with great intensity, and purity of colour. 



December 9, 1846.— J. S. Bowerbank, Esq., F.R.S., President, in 

 the chair. 



A paper on the application of Polarized light in Microsopic ob- 

 servations, by Mr. Legg, was read. After noticing the remarks of 

 Dr. Brewster, respecting the advantages likely to be derived from the 

 application of polarized light in the microscopic examination of deli- 

 cate structures, Mr. Legg described a series of polarizing apparatus, 

 which may be readily adapted to almost any microscope, consisting, 

 1st, of a bundle of plates of crown glass, from which the light is to 

 be reflected at an angle of 56° in which position one portion only 

 of the light is refracted, and another transmitted, each of which po- 

 sitions consists of light polarized in opposite planes ; this arrange- 



