1900] MICROSCOPICAL JOURNAL. 141' 



perfection of definition in that portion of the object im- 

 mediately under examination, and the rest may be ignor- 

 ed. If, however, a larger field be required, the flame, hav- 

 ing been focusaed, can then be turned broadside on, with- 

 out altering its other positions. For ordinary work this 

 is usual. 



In earlier days it was customary, after focussing the 

 light, to rack the condenser either up or down until the 

 field was fully illuminated, and we have heard that the 

 Quekett Club, which has done so much for amateur mi- 

 croscopistn, held two vehement rival schools, one of which 

 maintained that the condenser should be racked up and 

 the other that it should be racked down. All these mat- 

 ters have now been settled by the realization of the real 

 principle, and even more, perhaps, by the improvement 

 in objectives, by which, under such illumination as now 

 obtains, hidden structure has been brought to light that 

 was before not even suspected. It may be well to warn 

 beginners against racking the condenser so high as to drive 

 the slide up against a high-power objective. 



BIOLOGICAL NOTES. 



L. H. PAMMEL. 



Zymase in Wine Yeast. — Zymase is the name given to 

 a ferment which is found in cultures of wine yeast. The 

 fermenting power of zymase is destroyed by the pres- 

 ence of formalin O.OY per cent. Zymase does not resem- 

 ble enzymes in its properties but seems to be more allied to 

 protoplasm than to the group of proteoses and peptones. 

 (Wroblewski. Abst. in Jour. Chem. Soc. 77 & 78 : 167). 



Hydrocyanic Acid in Vicia Seeds. — According to 

 Bruyning and VanHaarst, hydrocyanic acid and hence 

 amygdalin or a similar substance is found in the seeds of 

 several species of Vicia as V. sativa (Journ'el Roy. Chem. 

 Soc. 77-78 ; 160). 



