ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 



503 



those of Trudeau and McCrae. The materials employed are empty 

 gelatin capsules, glass tubing, celloidin or collodion solution, a drying 

 rack, blow-pipe flame, and a small file. 



The end of the glass tubing is heated in the burner and while still 

 hot is passed through the lid of the capsule. When cool the capsule is 

 plunged in the celloidin solution and afterwards placed on the rack to 

 dry. The coated capsule is then filled with broth by means of a Pasteur 

 pipette and then immersed, glass tube end downwards, in a broth culture 

 tube and autoclaved at 1 atmosphere for 5 minutes at 120°. By this 

 procedure the gelatin becomes dissolved in 

 the broth. The gelatin may, however, be n 



removed by washing out the sac with hot 

 water. 



After inoculating the medium in the 

 sac by the aid of a Pasteur pipette the 

 glass tube is sealed up, a procedure re- 

 quiring considerable care and skill. 



Method for Cleaning Slides.* — L. 

 Jones recommends a washing powder 

 known as " Gold Dust " for cleaning old 

 and dirty slides. A strong solution is 

 heated to boiling and then removed from 

 the fire. As many slides as the vessel will 

 hold are at once dumped in and left there 

 for half an hour or so, but should be moved 

 about occasionally. On removing the slides 

 they should be washed in water and then 

 dried or passed through alcohol and then 

 wiped. Usually one bath is quite sufficient. 



Bottle for Cedar- Wood Oil.— F. Ties- 

 sen, of Breslau, makes a bottle for cedar- 

 wood oil, which has some useful features. 

 An ordinary glass phial (fig. 106) is fixed 

 to a circular leaden base: this ensures Fig. 106. 



stability. The stopper is a sphere of hard 



rubber or vulcanite. This ball is perforated to allow the passage of a 

 long stem, the upper end of which serves as a handle and the lower end 

 as the dropper. As the stem is not fixed in the ball it can be pushed 

 up and down so as to regulate the length for the quantity of oil in the 

 bottle. 



Germ- and Water-tight Stopper foriPlasks-f— Dr. H. Schottmiiller 

 describes a stopper which is air- and water-tight and also prevents the 

 entrance of germs. The stopper proper is fixed to the inside of a cap 

 which goes over the neck of the bottle. The outer surface of the stopper 

 and the inner surface of the neck are ground to fit accurately. The neck 

 of the bottle has a double lip to prevent the layer of cotton-wool which 

 is wound round the neck from getting wetted when fluid is poured out. 



* Journ. App. Micr., v. (1902) p. 1781. 



t Cbiitralbl. Bakt., 1" Abt., xxx. (1901) pp. 875-7 (3 figs.). 



