ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 



251 



disk. On this disk plates of air-freo agar or gelatin are made and are 

 then inoculated with properly diluted cultures or fluids containing 

 b icteria. On the bottom of the pan are placed pyrogallic acid solution 

 and a piece of caustic alkali. The plate is then turned over and placed 

 in the dish so that it rests on the three supports. The edge of the disk 

 is then made air-tight with paraffin or wax. The apparatus is then 

 placed in the incuhator, and after the necessary time has elapsed the 

 plate is removed and examined in the usual way. 



Another apparatus devised by the author obviates two difficulties, viz. 

 the slow withdrawal of the air and the difficulty of direct observation 

 of the culture. It consists (fig. 57) of a flask into the bottom of which 

 is let a tube, the long thin neck of the latter projecting into the broad 

 neck of the flask. The nutrient me- 

 dium is placed in the lower tube, 

 and in the upper caustic alkali and 

 pyrogallic acid. The neck of the 

 flask is closed with a rubber plug and 

 rendered air-tight with paraffin. 



Apparatus for Cultivating An- 

 aerobes.* — Bombicci uses an appa- 

 ratus for cultivating anaerobes, which 

 consists of a flat flask drawn out at 

 the bottom into a flat tube (fig. 58). 

 This receptacle holds about 10 ccm. 

 of nutrient medium, and after inocu- 

 lation, a caoutchouc stopper with two 

 tubes bent at right angles is inserted. 

 Hydrogen gas is passed through in 

 the usual way for half an hour and 

 then the tubes are closed with seal- 

 ing-wax, after which the apparatus 

 is placed in the incubator. 



(2) Preparing Objects. 



Demonstrating the Malaria Para- 

 site. | — Prof. P. Argutinsky fixes 

 the films in sublimate alcohol. 7 grin, 

 of sublimate are dissolved in 100 

 ccm. of hot 1 p.c. aqueous salt solu- Fig. 58. 



tion, and when the solution is suf- 

 ficiently cool 100 ccm. of absolute alcohol are added. The films are 

 immersed in the foregoing for from 5-8 minutes and then washed in 

 absolute alcohol, after which they are treated with iodine-alcohol. The 

 iodine-alcohol is prepared by mixing 100 ccm. of absolute alcohol and 

 2 ccm. of 1 p.c. alcoholic tincture of iodine. In this they remain for 

 10 minutes and are then transferred to absolute alcohol for 10 minutes, 

 after which they are dried with blotting-paper and stained at once or on. 

 some following day. 



* Centralbl. Bakt., 1" Abt. Ref., xxxi. (1902) p. 154. 



t Arch. f. Mikr. Anat. u. Eutwickl., lix. (1901) pp. 319-28 (4 pis. and 107 figs.). 



