ZOOLOGY AND BOTANY, MICROSCOPY, ETC. (''>."> 



traces of acid. 5. The sections are then mopped up -with blotting- 

 paper, and after a momentary immersion in absolute alcohol are cleared 

 up in bergamot oil, then xylol and balsam. 



Micrographic Study of Leather.* — H. Boulanger gives the follow- 

 ing methods for demonstrating the microscopic appearances of raw and 

 tanned hide. In the former case pieces of skin are soaked for 12 hours 

 in a solution composed of distilled water 5, glycerin 5, aceton 90. They 

 are then allowed to dry, imbedded in hard paraffin, stained and mounted 

 in the usual way. In the process for preparing sections of cowhide 

 tanned with oak-bark and carried with degras, a small strip of leather 

 about 10 mm. wide is taken, and the flesh side shaved away until the 

 piece has a thickness of about 2 mm. The shaved strip is placed in 

 melted tallow, not too hot, for about a quarter of an hour. After 

 cooling the strip is imbedded in hard paraffin, and cut in a Ranvier 

 microtome. The sections are degreased with xylol, then washed two or 

 three times in alcohol and stained with Weigert's fuchsin. The staining 

 takes about 3 hours. The Weigert solution is poured off, and a few 

 drops of absolute alcohol remove excess of dye and differentiate the 

 various parts. Usually the section is dehydrated with alcohol, cleared 

 up with xylol, and mounted in balsam. 



C3) Cutting:, including- Imbedding- and Microtomes. 



Arrangements for Utilising the Entire Cutting-edge of Micro- 

 tome Razor s.| — C. Funck refers to the troubles frequently met with in 

 pathological sections, arising from the notching or bluntness of the 

 microtome knife, and points out the great advantage which would arise 

 if the whole of the cutting-edge could be used : the precious time now 

 required for re-sharpening could then be saved. The author describes 

 two methods of attaining his purpose, the first of which depends on 

 xi*/)plementary jaws, and does not involve any alteration in the micro- 

 tome itself. Suppose that in fixing the razor the handle is turned 

 towards the operator, and that it is the further end which one wants to 

 be able to bring into use. But if the operator draws the blade towards 

 himself the remote end becomes free. To overcome this difficulty the 

 author suggests that, between the extremity of the razor and the fixed 

 jaw, an additional jaw (fig. 154, a) could be inserted. This additional 

 jaw would be fixed firmly by the prolongation P, whose sectional form 

 would be analogous to that of the razor. If the razor should be 

 turned in the way opposite to that described, the form of jaw would 1 >e 

 analogous and symmetrical to that shown in fig. 154, a. If the micro- 

 tome should not be provided with this upper transversal stem T, it 

 would be convenient and less costly to make in one piece the two jaws 

 connected to each other by their bases, as shown in fig. 154, b. 



Although the method gives the use of an increased amount of edge, 

 it does not effect anything for the handle end. For this purpose the 

 author has designed his second method, which consists in modifying the 



* Bull. Soc. Encouragement, Feb. 1908. See also Nature, lxxviii. (1908) pp. 

 18-19 (2 figs.). t Zeitschr. wiss. Mikrosk., xxv. (1908) pp. 53-60 (1 figs.). 



