ZOOLOGY AND BOTANY, MICROSCOPY. ETC. 



347 



but is not altogether satisfactory. The method of stopping-off in the 

 immersion-condenser has, so far, been found to be the best. The triple 

 Abbe quartz-condenser, N.A. 1 • 45, is equipped with a star-diaphragm 

 which stops off the middle part of the condenser to an aperture of 1 "0. 



With accurate centring, the preparation shines out brightly and 

 clearly in its specific fluorescence-light on a black-grey ground. 



The importance of the new method lies in the fact that it supplies 



a new means of differentiating between similar bodies. 



Thus organic 



Fig. 61. 



substances of similar morphological, but of differing chemical, nature are 

 found to haye distinctive characteristics. Small quantities of ergot in 

 flour are readily detected by a striking difference in colour. 



Reichert has in preparation a phosphorescence-Microscope depending 

 on a combination of the ordinary microscope with Becquerel's phosphoro- 

 scope ; but the technical difficulties involved are greater than in the 

 design of the fluorescence-Microscope. 



Baker's New Lever Fine-Adjustment.* — Fig. Gl shows a curved 

 lever fine-adjustment lately adopted by Messrs. C. Baker & Co. A A are 

 milled heads actuating a micrometer screw whose motion is conveyed by 



* C. Baker and Co., London, W.C, Catalogue; Knowledge, xxxv. (1912) p. 515. 



2 B 2 



