664 



SUMMARY OF CURRENT RESEARCHES RELATING TO 



spiral spring, intended to press upward a little platform. The solid 

 carbonic acid is accumulated on this platform, and the action of the 

 spring forces it against the microtome-stage. An object on the stage 

 therefore experiences a freezing effect. The outer and inner brass 

 cylinders and microtome-stage are threaded and fit compactly together. 

 The size of the whole, exclusive of the actual stage, is 45 mm. diam. 

 and 85 mm. high. The author found that the cost of 1 hour's freez- 

 ing was only one penny. The object to be frozen was moistened with a 



few drops of water, and the frost fastened it firmly to the stage. The 

 author found he could cut a long series of faultless sections 5 /x thick 

 from rather large objects, and he seems to have been well satisfied with 

 his results. He also found that lie could apply carbonic acifr to the 

 cooling and hardening of paraffin-imbedded objects. 



Minot's Small Microtome.* — M. Wolff has designed a small form 

 of the Minot-Zimmermann Microtome, Model I., and states that it 



* Zeitschr. wiss. Mikrosk., xxvi. (1909) pp. 84-104 (5 figs.). See also a special 

 pamphlet, (No. 21) E. Zirauiermanu, Leipzig. 



