MICROSCOPICAL TECHNIQUE. 423 



cellulose fibres by staining re-agents is dependent on a chemical 

 process, or merely on a mechanical union of the particles of the 

 pigment with those of the cellulose, Herr G. Spohn has attempted 

 to set this matter at rest by a careful microscopical examination of 

 cotton-wool stained by mineral pigments. He found no change 

 whatever in the structure of the fibre itself. Even when the fibres 

 were macerated before staining with alizarin, they acted sharply as 

 a carrier of the pigment, on which the macerating fluid acts che- 

 mically. In all cases, according to these observations, the com- 

 bination of the pigment with the fibre depends entirely on purely 

 mechanical causes. — Pharmaceutical Joiiriial. 



Mounting" Spores of Equisetnm.^— Mr. T. D. Schoonmaker 

 gives his method for mounting these spores as follows : — Take a 

 zylonite or rubber cell, ^ of an inch in diameter and about ^^ of 

 an inch, or a little less, in depth, and glue it fast to the slip. After 

 it has become firmly attached to the glass, cut with a file several 

 creases in the cell, half the depth of the cell, or about i/i6th of 

 an inch. Spread the spores evenly in the cell, and attach the cover- 

 glass by spreading on a little marine glue betw^een the filings. This 

 method confines the spores and allows enough moisture from 

 the breath to pass through the triangular openings to set the 

 spores " dancing." 



Mounting Medium for Algse and Fungi, f— Dr. A. A. Julien 

 recommends the following solution, an indirect outcome of Ripart 

 and Petit's formula, for mounting organisms with endoplasm of 

 ordinary density, e.g.^ most of the filamentous algae : — Copper 

 chloride, o'l grm. ; copper nitrate, o'l grm. ; chloral hydrate, o'5 

 grm. ; distilled water, just boiled, loo ccm. The trace of acidity 

 is removed from the solution in the following manner : — Another 

 solution is prepared of a few grms. of any soluble copper salt ; to 

 this a weak solution of caustic potash is added in slight excess ; 

 the hydrated copper oxide is then washed thoroughly, first by 

 decantation, and then upon a filter. The purified residue is then 

 thrown into loo ccm. of the preservative fluid already prepared, 



* The Observer, iv. (1893), PP- 198—199- 



\ Journ. R. Alter. Soc, 1893, p. 566, ixom Journ. Netu York 

 Micr. Soc., X. (1893), P- 39- 



