138 THE MICROSCOPE. [June, 



3S. What -cuill prevent rust on the steel parts of the B. d' L. 

 and Scha??ze niicroto?ncs ? I Jind they ivill still rust after 

 applyiiig vaselitie and kerose?ze. 



The microtome should be well cleaned and carefully dried in 

 hot air. Vaseline or even machine oil will usually prevent rust. 

 All rusty spots should be well polished out. because such spots 

 often continue to rust even under a coat of varnish. 



39. What is a good way to prepare the vieseiitery to demon- 

 strate its histology ? 



Stretch and pin a portion of the fresh mesentery to a cork, 

 harden it in alcohol, stain, cut or tear a portion, and mount in 

 Farrant's solution or balsam. 



40. Jl'hat is a good way to jnotnit a prothallus of ferti ? 

 Soak it and mount it in a mixture of glycerine i part, alcohol 



I part, and water 2 parts. 



41. I have some dry speci??iens of moss. How shall I treat 

 the7nfor mounting — dry or iii balsam? 



Mount some of the conceptacles drv — just as they are. Other 

 parts may be soaked in water until softened, arranged or straight- 

 ened, then into strong alcohol, clove oil, and then balsam. 



42. What is the way to examine fungus on tobacco leaves., 

 etc.^ and how may pertnaitent mounts be made? 



These are best cut fresh and green, and examined in camphor 

 water. For permanent mounts, harden in alcohol, cut. stain, and 

 mount in camphor water or glycerine. Some specimens may be 

 mounted dry also. 



43. What is the best ??iedium for trichina. I have tried 

 glycerine^ Farranf s solution, and dry. They all disappear 

 within a year. — H. M. Farr. 



Trichinous muscle should be well hardened in alcohol, then 

 cut. stained with carmine, and mounted in Farrant's solution, or 

 balsam ; will be as permanent as any other pathological mount. 



44. I have difficulty with my botaiiical preparations. The 

 pith seems clogged with some opaque stibstance, not air bub- 

 bles. What causes these dark spots? Also, what is the best 



fluid for preserving specimens of wood before cutting? — L. 



This query does not define the spots clearly, nor mention the 

 sort of wood affected. The '' spots" may be crystalline, resinous, 

 or fungoid. Define the spots more precisely, or send a mounted 

 specimen to the writer for diagnosis. All tender wood should be 

 preserved in alcohol. Hard, mature wood may be simply dried, 

 and should be boiled to soften them somewhat before cutting. 



45. Where can the Taylor freezing microtome be purchased., 

 and at what price? — A. E. McKay. 



The price is $15, and it can be obtained from Dr. Thomas 

 Taylor, 238 Mass. ave. N. E.. Washington, D. C. 



