PROCEEDINGS OF THE SOCIETY. 753 



he had also made a similar specimen of his own, but the conclusion 

 be came to was that the appearances described were due to some sort 

 of diffraction effect and that they were in fact out-of-focus appearances. 



Mr. J. Mayall, jun., called attention to the fact that a Nobert 

 19-band test-plate had been successfully mounted in Prof. Hamilton 

 Smith's medium having a refractive index of 2*4, the result being to 

 render the lines very much more visible than had been the case before. 

 The preparation was made by Dr. van Heurck, and was attended with 

 considerable difficulty. 



Mr. Crisp said they had received from Prof. W. A. Eogers, of 

 Cambridge, U.S.A., a collection of uj)wards of 50 slides showing the 

 action of a diamond in ruling lines upon glass. The series was 

 accompanied by a descriptive paper which when printed in the Journal 

 would enable the Fellows to compare it with the slides. 



The President said that Prof. Eogers had expressed the hope that 

 some one might feel sufficiently interested in the subject to make a 

 careful study of the slides. They had not yet had any opportunity 

 either of examining the slides or reading the paper, but their best 

 thanks were due to Prof. Eogers for his valuable donation. 



A vote of thanks to Prof. Eogers was carried by acclamation. 



Mr. Crisp, in exhibiting Theiler's " Universal Pocket Microscope," 

 read some of the press notices of it and commented on the extravagant 

 manner in which it had been referred to in some journals (sup-a, 

 p. 704). 



Dr. Maddox said that since the last meeting he had continued hia 

 experiments on the feeding of insects with bacilli, and had fed both 

 the wasp and the blow-fly formerly alluded to, with the anthrax 

 bacillus. They had lived on through the month until that very hot 

 day when the thermometer rose to 136° in the sun, when they suc- 

 cumbed to what he believed was heat asphyxia, so that he was unable 

 to attribute their deaths to any effect of the bacilli (supra, p. 606). 



Mr. "Waters read his paper " On the use of the Avicnlarian Man- 

 dible in Classification," the subject being illustrated by drawings. 



Mr. Cheshire described a method of mounting which ho had found 

 of groat advantage with the particular class of preparations with which 

 he had lately been engaged, and he proposed to give some account of 

 it, as likely to be of interest to others similarly working. All present 

 were no doubt aware of tlio great value of glycerin as a mounting 

 medium for delicate structures, Canada balsam being destructive to 

 soft tissues and cells. Glycerin also possessed a marvellous immunity 

 from freezing. The great difficulty about its use for mounting pur- 

 poses generally arose frorn the fact tliat when once the surface of 

 glass bad been contaminated with glycerin it was very troublesome 



