480 MICROSCOPICAL TECHNIQUE, 



drop on a glass slip, spreading it somewhat with a glass rod. 

 Touch the drop with a piece of zinc plate cut to a point, pushing 

 the point well towards the centre. The crystals will form in 

 feathery masses, w^hich make a very beautiful object for the 

 microscope. 



New Multiple Staining Fluid.- The Sheffield Medical Journal 

 says that Unna differentiates bacilli in tissues by a polychromic 

 methylene blue solution, which contains methylene red and violet 

 in addition to the blue. The sections are transferred from alcohol 

 and allowed to remain in the stain for at least ten minutes. They 

 are then passed through water into 33 per cent, tannic acid solu- 

 tion to decolorise, allowed to remain from two to five minutes, 

 then rinsed wdth water to enable the exact tint to be observed more 

 readily. If satisfactory, after a thorough washing with water, the 

 sections are placed in absolute alcohol, or a solution of gold 

 orange in the same if a yellow counter stain be desired, cleared in 

 oil of bergamot, and mounted in balsam. 



If the excess of stain is not readily removed, a few minutes' 

 immersion in 25 per cent, nitric acid, followed by dilute spirit, 

 water, and absolute alcohol respectively, will effect its removal. 

 By adopting this method, it is said to be possible to distinguish 

 two kinds of nuclei (violet and blue) — the fibrine and the proto- 

 plasm of the plasma-cells. The bacilli stain red, whilst the mucus 

 surrounding them is blue, and the organisms are said to appear in 

 their natural character "in fish-roe-like masses of vegetable mucus." 

 It is claimed that the process is particularly suitable for use in the 

 study of leprosy." It appears to depend upon the property, also 

 utilised by NicoUe, by which tannin converts methylene blue into 

 an insoluble form. 



. A LIVING ILLUSTRATION of the truth of the evolution theory 

 has been dredged in 392 fathoms off one of the Galapagos Islands, 

 in the shape of a stalked crinoid, or sea lily, in which are united 

 the characteristics of three distinct fossil genera of the same group 

 of organisms : — Apiocrinus of the Bradford clay deposits, Hyo- 

 cnnus, and Rhizocrinus. This interesting survival of a very old 

 and complex type will shortly be described by Mr, Alexander 

 Agassiz. — The Afnerican Naturalist. 



