524 



SUMMAEY OF CURRENT RESEARCHES RELATING TO 



and then can be used, after appropriate adjustment by moans of its rod, 

 as an indicator on tbe wbeel-tooth, if one wishes to prepare thicker sec- 

 tions of 20 fx and upwards, and to save wear and tear on the gear. 



For cutting celluloid objects (fig. 143) under alcohol, a thin metal 

 tray is used, which bears on its under side a soldered-on mouthpiece of 

 the shape and size of the inner object collar, thus alio tving it to fit on to 

 the outer collar. A small piece of paraffin is melted, and cements the 

 celluloid plug on to the proper place ; the tray is then filled with 70 per 

 cent, alcohol, and cutting proceeds. Attention must of course be paid 

 to orientation. This arrangement is also followed for cutting sections 

 of plants between elder pith or liver. 



Fig. 143. 



The microtome produces good paraffin serial sections of 5 /*, cellu- 

 loid in alcohol 10 //., and pith 20 //.. The area of the slice is about a 

 square centimetre. 



The inventor recommends the advantages as (1) manifold appli- 

 cability, on account of easy adjustability of knife, object and catch ; 



(2) small knife, with accurate cut and easy withdrawal of section; 



(3) low price. 



Bettling, C. J. — TJeber die neuen.Bogen-Mikrotome. (On the new Circular 

 Microtomes.) 



[An interesting review of microtomes in general and of circular microtomes in 

 particular.] Zeitschr.f. angew. Mikr., VI. (1900) pp. 1-6 (2 figs.). 



