28 The Microscope. 



histoiy and to bacteriological work, and by its low price it 

 realizes a progress which I think it proper to encourage. 



With the excellent apparatus of MM. W. and H. Seibert, 

 of Wetzler (vertical illuminating apparatus),* this objective 

 readily resolves a drj" mounted Amphipleu.ra pellucida, not 

 only into stride but into heads. 



WAVS • 

 ANDIAEANS 



A New Method of Stain iNG.f — Martinotti's solution is made 

 by saturating alcohol with picric acid and with nigrosine. Two 

 parts of this solution and one part of aniline water are mixed 

 together and allowed to evaporate in the open air. The crystals 

 deposited are dissolved in prool spirit. This is also evaporated 

 and olive-green, cubical cr^^stals obtained soluble in water, in 

 ether and in alcohol. With them is made a 2 per cent, solution, in 

 alcohol for tissues, in water for micro-organisms. Sections are 

 first stained by Beale's or Orth's carmine, decolored in acidulated 

 alcohol, washed in water, dehydrated and placed in the alcoholic 

 solution of picro-nigrosine, where tliey remain for from 2 to 10 

 minutes till stained chestnut brown. Decolor in an alcoholic 

 solution of oxalic acid, dehydrate, clear, and mount in balsam. 

 By this the nuclei are stained red, the protoplasm deep yellow, 

 the connective tissue light green, elastic fibres violet, the carti- 

 laginous substance yellow. 



To stain micro-organisms within the tissues, after coloring 

 with carmine, decolor by Gram's method (or that of Koch-Ehr- 

 lich for Bacillus tuberculosis), and place for 5 minutes in an aque- 

 ous solution of picro-nigrosine, finishing as already described. 



*MM. Seibert's vertical illuminating apparatus was invented and made 

 twenty years ago by Messrs. R. & J. Beck, of London. It is the " Vertical 

 Illuminator ' ' which has been for that length of time used in England. 

 [The forgoing footnote is added by the editor of the Journal de Micrographie, 

 who has fallen into error by giving the Messrs. Beck credit for the invention 

 of the Vertical Illuminator. It is the invention of Prof Hamilton L. 

 Smith, of Geneva, N. Y., the American authority on the Diatomaceae. — 

 Editor The Microscope.] 



tLa Riforma Medica. Cf Bui. Soc. Beige de Micros. 



