646 



SUMMARY OF CURRENT RESEARCHES RELATING TO 



and Ramsden ocular. The tube can be applied to several patterns of 

 preparation stands supplied by the firm. 



Photomicroscope for Ultra-violet Rays and its Significance for 

 Histological Investigations, especially of Hard Structures.* — W. 

 Dreck fully describes his methods, which seem to have been very suc- 

 cessful. He gives several photographic plates of diatoms and of sections 

 of teeth and bones. 



Marx, H. — Ein handliches Obduktionsmikroskop. 



Zeit.f. Medizinalbcamte Jahrg., xx. (1907) No. 21, pp. 744-5. 



(2) Eye-pieces and Objectives. 



Reichert's Spectral-ocular.f — This ocular (fig. 147) is due to Abbe, 

 and has the prisms arranged rectilinearly. By means of a spiral move- 

 ment the ocular lens can be focused accurately upon the slit which can 



Fig. 147. 



be regulated both in breadth and height. There is a comparison prism, 

 a lateral stage, and illuminating mirror, as well as a measuring apparatus 

 for Fraunhofer's lines. 



Reichert's Index-ocular 4 — This auxiliary, constructed after 

 Bourguet's design, is shown in fig. 148. Its peculiarity consists in the 

 externally adjustable index by means of which any point in the field of 



* S.B. Gesell. Naturf. Freunde, 1906, No. 4 (April) pp. 108-25 (18 figs.), 

 t C. Reichert, Vienna, Catalogue, Mikroscope, p. 58, fig. 56. 

 X Tom. cit., p. 60, fig. 60. 



