.DEMONSTRATION OF CILIA. 465 



of the cover, and the slide put away in a moist chamber, in 

 order that the water may evaporate very slowly and be 

 changed very gradually for the glycerin mixture; if this 

 precaution is not taken, shrinkage may occur. When the 

 exchange has taken place, strong glycerin may be added, and 

 gradually substituted for the dilute glycerin. 



Certes states that the organisms thus prepared are fixed 

 perfectly in their natural form, and allow of the study of the 

 minutest detail of cilia, flagella, and the like, with the highest 

 powers ; the green coloration of Euglenae and Paramecia is 

 preserved. The nulear structures are sharply brought out 

 by the picro-carmine. 



SAVILLE KENT and BERTHOLD (Manual of the Infusoria; 

 Journ. Roy. Mic. Soc., 1883, p. 451) prefer a brownish-yellow 

 solution of potassium iodide to osmic acid for fixing. 



The employment of vapour of iodine has been described, 

 66. 



Du PLESSIS (Voar et YUNG, Trait. Anat. Comp. Prat., p. 92) recommends 

 fixation with 0'2 per cent, solution of corrosive sublimate. Let the prepara- 

 tion dry up, and if the organisms have preserved their shape, stain and 

 mount in balsam. 



FOL (Lehrb., p. 102) fixes delicate marine Infusoria (Tintinnodea) with, 

 the perchloride of iron solution, 52, added to the water containing them, and 

 stains with gallic acid as directed 231, and states that this is the only 

 method that has given him good results, especially as regards the preservation 

 of cilia. 



KUNSTLEE (Journ. de Microgr., 1886, pp. 17 and 58). For Monadina. 

 Fixation by means of a drop of very concentrated osmic acid solution (a 

 grm. of osmium dissolved in only a few c.c. of distilled water). 



LONGHI (Bull. Mus. Zool. Univ. Genova, 4, 1892 ; Zeit. 

 /. wiss. Mik., ix, 4, 1893, p. 483) has obtained good results by 

 means of sulphate of eserin. A 1 : 10 per cent, solution is 

 taken, and to each 10 c.c. of it one drop of 1 per cent, subli- 

 mate solution is added. 



See also the methods of FABRE-DOMERGUE, Ann. de Microgr., 

 ii, 1889, p. 545, and of SCHEWIAKOFP, BiUioth. Zool., v, 1889, 

 p. 5; Journ. Boy. Mic. 8oc., 1889, pp. 832, 833; ZOJA, Boll. 

 Sci. Pavia, 1892 ; Zeit. f. wiss. Mik., ix, 4, 1893, p. 485. 



860. Demonstration of Cilia (WADDINGTON, Journ. Roy. Mic. 

 Soc., 1883, p. 185). Solution of tannin, or a trace of alcoholic 



solution of sulphurous acid. 



30 



