ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 315 



specimens remain cloudy after liberal use of absolute alcobol, this is 

 due to insufficient immersion in the turpentine batb. 



Mode of rendering visible the closing Membrane of Bordered 

 Pits.* — Herr A. Zimmermann recommends for this object staining with 

 haematoxylin (in Bohmer's solution), and clearing with oil of cloves and 

 Canada balsam. If slightly tinged, the " torus " alone then takes up 

 the pigment strongly, while all the other membranes are almost entirely 

 colourless. By this method the torus is rendered visible even in 

 relatively thick sections and with low magnification. 



Mounting small Organisms— Disaggregation of Rocks.| — Sig. D. 

 Pantanelli who recently suggested a method for mounting small 

 organisms found in the residues from finely divided rocks, by using a 

 mixture of collodion and oil of cloves, has, on account of the impurities 

 in the latter, and the difficulty of making elegant preparations, now sub- 

 stituted for it salicylic ether (C 9 H In 3 ), which, on being evaporated at 

 a temperature of 60°, leaves the collodion unaltered, while at ordinary 

 temperatures it keeps viscid sufficiently long for making the prepara- 

 tion. 



Tempere advised that rocks refractory to acids should be disaggre- 

 gated by boiling them in a concentrated solution of sulphate of soda, 

 the act of crystallization completely breaks up the rock ; when used for 

 diatoms this method succeeds very well with porous rocks, and serves 

 excellently for separating out the foraminifera from argillaceous or 

 calcareous rocks, which are not reduced by repeated immersion in water. 

 Having experimented with porous, calcareous, and compact argillaceous 

 rocks, the author has succeeded in separating out, without damage, the 

 most delicate foraminifera, and still more easily radiolaria and diatoms. 

 Whenever siliceous organisms are sought for, the acid process should be 

 adopted, and whenever this fails to break up the rock, the solution of 

 sulphate of soda should be tried. 



KtXHNE, H. — Ueber em kombinirtes Universalverfabren, Spaltpilze im tbieriscben 

 Gewebe nachzuweisen. (Oq a combined universal process for demonstrating 

 bacteria in animal tissues.) Dermatol. Studicn (Unna), 1887, pp. 9-14. 



M a n t o n. W. P. — Rudiments of Practical Embryology, being working notes with 

 simple methods for beginners. Microscope, VIII. (1888) pp. 15-8. 



(3) Cutting-, including- Imbedding-. 



Application of Paraffin Imbedding in Botany 4 — Dr. J. W. Moll 

 enthusiastically recommends paraffin imbedding for botanical prepara- 

 tions. The reasons given why this method has not hitherto been more 

 generally adopted are that tissues preserved in alcohol are unsuitable, 

 and that it has usually been tried with full-grown parts, for which it is 

 not so well adapted. 



The procedure is as follows : — Take, say, fresh tips of some primary 

 or secondary root 1-2 cm. long, and fix in watery 1 per cent, solution 

 of chromic acid, or a saturated solution of picric acid, or, best of all, a 

 modified Flemming's mixture (chromic acid 1 per cent., osmic acid 

 • 02 per cent., acetic acid ■ 1 per cent.). 



Herein the root-tips remain for twenty-four hours, and then the acids 



* Zeitschr. f. Wiss. Mikr., iv. (1887) pp. 216-7. 



t Atti Soc. Tosc. Sci. Nat., vi. (1887) Proc. Verb., pp. 12-13. 



X Bot. Gazette, xiii. (1888) pp. 5-14. 



