1893.] THE MICKOSCOPE. 35 



but it requires from half an hour to several hours to produce a 

 perfect print. When it has become dark enough, immerse the 

 paper in a dish of clean water, which must be changed every few 

 minutes, until the yellow part becomes perfectly white. The 

 print can then be mounted in a scrap-book. — Adapted from 

 " Work." 



The Doctor's Microscope. — The microscope has now be- 

 come an indispensable instrument in medical practice, without 

 which the physician must often work without the knowledge which 

 his patients justly expect him to command. — -Boston JMedical and 

 Surgical Journal. 



Oil of Anise-seed as an Imbedding Medium for the 

 Freezing Microtome. — Dr. H. Kiihne has discovered that oil 

 of anise-seed may very successfully be used as an imbedding 

 medium for cutting sections with the freezing microtome. The 

 procedure is as follows : Pieces about 2 mm. thick are placed 

 on blotting-paper to remove the alcohol, and then immersed in a 

 capsule containing the anise-seed oil for 12-24 hours. When 

 thoroughly saturated with the oil — and this is easily recognized 

 by the clearing up of the material — the pieces are placed on the 

 microtome and sectioned. The sections are temporarily trans- 

 ferred to anise oil on a glass rod. and when all the piece is sec- 

 tioned, are placed in alcohol (twice repeated) to remove the oil. 

 When all the oil is removed, the sections are ready for staining. — 

 Jour. Royal j\licr. Soc. Oct.. i8g2. 



Methylen-blue Staining of Nervous Systems of Inver- 

 tebrata. — Herr O. Burger, when investigating the nervous sys- 

 tem of Nemertine worms, seems to have obtained very good re- 

 sults, judging at least from the colored illustrations said to be 

 faithful representations, by injecting these animals with a fluid 

 made by dissolving 0.5 grm. methylen-blue in 100 grm. of \ per 

 cent, cooking salt solution, or with a simple watery solution of 

 the same strength. Sea-water, in which methylen-blue is per- 

 fectly soluble, is quite unsuitable for the purpose. The injections 

 were made frequently, one injection imparting only a faint stain- 

 ing. The best period for injecting was in the half-dead con- 

 dition, or in that state when the animal or parts thereof still show 

 signs of life. The time required for bringing about good in- 

 jection results was at least 6-S hours, and sometimes much 

 longer. After a time the author found that satisfactory results 

 were more easily obtained bv merely injecting a part or organ. 

 The preparations were fixed with dilute picrate of ammonia and 

 afterwards put up in glycerine to which a trace of ammonia had 

 been added. 



The staining does not last very long, and hence in examining 

 a specimen it is advisable to begin at those parts from which the 

 blue color first disappears, viz., at the periphery. — JMittheil. Zo. 

 Station zu Neafel — 1891 . 



