262 



SUMMARY OF CURRENT RESEARCHES RELATING TO 



Fig. 64. 



Fig. 65. 



Fig. 66. 



£&\ 



Permanent Preparations in Hermetically Sealed Tubes.*— Mr. H. 



F. Nachtrier describes a method for keeping animals and botanical 

 specimens in tubes hermetically sealed. Glass tubing of a size just 

 admitting the specimen and considerably longer than the final sealed 

 tube is to be is employed. One end is closed, the tube filled with 80- 

 70 per cent, alcohol, and the specimen carefully introduced. Nearly 

 all the alcohol is then poured off (tig. 64). The tube is tben drawn 



to a point at some distance from 

 the object and broken off at the 

 neck (fig. 65). It is then filled by 

 means of a tube-funnel with a long 

 small end. When filled, the end is 

 sealed in a Bunsen flame (fig. 66). 

 Care is required in sealing, but the 

 secret of success consists in making 

 as small a neck as is practicable. 

 Flemming's mixture of alcohol, gly- 

 cerin, and water usually answers 

 better than pure alcohol. The in- 

 troduction of a slip of milky or 

 black glass is an improvement in 

 some cases, as it shows up the ob- 

 jects better. 



Permanent Preparations of 

 Urinary Casts, f — Dr. L. N. Bos- 

 ton has found the following me- 

 dium suitable for preserving all 

 kinds of casts. Liquor acidi arse- 

 niosi (U.S.P.), one fluid ounce ; salicylic acid, half a grain ; glycerin, 

 two fluid drachms. Warm slightly until the ingredients are dissolved, 

 then add acacia (whole tears) and warm again until the solution is satu- 

 rated. After subsidence decant the clear supernatant fluid. A drop of 

 formalin may be added to this mixture if desired. 



The casts are obtained from urine by sedimentation, the super- 

 natant fluid being decanted off. A drop of the deposit is pipetted on 

 to a slide, and if casts be present, the fluid is evaporated nearly to 

 dryness. A drop of the medium is then placed in the centre of the 

 urine-patch and the two mixed by carefully stirring them together with 

 a needle. A cover-glass is then put on. The slightest pressure or the 

 application of heat is usually destructive of casts. The slide is now 

 put in a cool place for a few hours in order that hardening may be 

 complete, and the preparation ringed round with zinc- white. 



(3) iCuttiiig, including- Imbedding and Microtomes. 



Schaffer's Paraffin-block Quick Cutter.^ — Prof. Jos. Schaffer's appa- 

 ratus which he has now used for three-and-a-half years, is represented 

 in fi<*s. 67 and 68. A circular domed iron base plate a, planed flat at the 

 top, bears firmly screwed in its centre, but projecting above it by means 



* Science, s. (1899) pp. 771-2 (3 figs.). t Micr. Bull., xvi. (1899) p. 34. 

 J Zeit. f. wiss. Mikr., xvi. (1900) pp. 417-21 (2 figs.). 



