592 PKOCEEDINGS OF THE SOCIETY. 



the value of deep eye-pieces, there was probably none as regarded the 

 desirability of securing the best possible definition, whatever amplifi- 

 cation was used. He considered that with Huyghenian eye-pieces of 

 less than an inch focus there was a serious deterioration of the image. 

 The eye-pieces now exhibited gave the sharpest definition of any of 

 similar foci he had hitherto been able to examine. 



Mr. Crisp explained the new method devised by Dr. Ehrlich, the 

 assistant of Dr. Koch, for preparing the bacteria of tuberculosis, 

 which constituted a considerable improvement upon the original 

 process. It produces a more intense colour in the bacteria, so that 

 they appear larger, and can be recognized with a lower power, even, 

 it is said, of 250 diameters (see p. 572). 



Prof. Abbe's process of increasing the consistency of pure cedar- 

 oil, so as to render it less fluid and therefore more convenient for 

 use as a homogeneous-immersion fluid, was explained by Mr. Crisp. 

 The oil is spread out in thin layers, and exposed to the action of the 

 air and light for a long time, until it becomes of the consistency of 

 castor-oil (see p. 551). 



Mr. W- F. Petterd's letter was read accompanying a collection of 

 diatoms from Tasmania. 



Mr. A. Certes' letter, reiterating his claim to the discovery of 

 a method of staining the nucleus of living Infusoria, was read by 

 Mr. Crisp, who said that the author of the interpolation by which 

 such a claim was described as " erroneous," now agreed that he was 

 mistaken in the view he had expressed, not having in fact sufficiently 

 noticed that the claim related essentially to the nucleus of the living 

 animals (see p. 576). 



Mr. Crisp called attention to a process devised by E. Korschelt, 

 of Freiburg, for preserving Infusoria and Amcebce by the use princi- 

 pally of osmic acid and chromic acid, no method having hitherto been 

 found for the latter organisms. Dr. A. Gruber had also succeeded 

 in preserving Heliozoa by the method, in excellent condition (see 

 p. 574). 



Mr. Pv. Miller's description of his caoutchouc cement for making 

 and sealing cells was read, in which he stated that he did not claim 

 to have discovered any new material, but to have accidentally hit 

 upon a new method of combination. The material so obtained was 

 singularly easy to work, and reliable in its results (see p. 579). 



Dr. Van Heurck's letter was read describing favourably his 

 further experiences with the Swan electric lamps and Faure-Reynier 

 accumulators (see p. 557). 



