630 APPENDICES. 



The case is double-walled, and the water contained in the interspace 

 is heated from below. It is supported on four legs, and the two 

 front ones move in grooves in the case, so that the latter can be 

 placed obliquely at the angle required and secured in position by 

 screw-clamps. It is employed for coagulating sterile liquid serum, 

 and for solidifying nutrient agar-agar so as to give them a sloping 

 surface. 



Hueppe's Serum Inspissator. By the new process the serum 

 is obtained with every possible precaution, and solidified at once in 

 Hueppe's apparatus (Fig. 44). 



Glass Capsules. Small capsules or hollowed-out cubes of 

 crystal glass are employed for cultivation on solid blood-serum, on 

 nutrient gelatine, and on agar-agar. They may be procured of 

 white and blackened glass, and are provided with glass slips as 

 covers. 



(K) APPARATUS FOR STORING, AND FOR CULTIVATIONS IN, LIQUID 



MEDIA. 



Lister's Flasks. Lister devised a globe-shaped flask with two 

 necks a vertical and a lateral one. The lateral one is a bent spout, 

 tapering towards its constricted extremity. When the vessel is 

 restored to the erect position after pouring out some of its contents, 

 a drop of liquid remains behind in the end of the nozzle, and 

 prevents the regurgitation of air through the spout. A cap of 

 cotton wool is tied over the orifice, and the residue in the flask kept 

 for future use. The vertical neck of the flask is plugged with 

 sterilised cotton wool in the ordinary way (Fig. 60). 



Sternberg's Bulbs. Sternberg advocates the use of a glass 

 bulb, provided with a slender neck drawn out to a fine point and 

 hermetically sealed (Fig. 62). 



Aitken's Test-tube. This is an ingenious device for counter- 

 acting the danger of entrance of atmospheric germs on removal from 

 the ordinary test-tube of the cotton-wool plug. Each test-tube is 

 provided with a lateral arm tapering to a fine point, which is 

 hermetically sealed (Fig. 62). 



Drop-culture Slides. About a dozen or more thick glass 

 slides with a circular excavation in the centre are required for 

 drop-cultures (Fig. 48). 



Vaseline. A small pot of vaseline with a camel's-hair brush 

 should be reserved especially for use in the preparation of drop- 

 cultures. 



