and Laboratory Methods. 



2207 



of any size serves just as well until it rusts out. It is only necessary to provide 

 a perforated grate. This grate should be far enough from the bottom so that 

 the space between them will contain enough water to last an hour. (See Fig. 2.) 



Media cooker. — A double boiler or rice boiler. (Fig. 3.) 



Graniteware bread pans with a piece of window glass for cover. 



Funnel. — A three or four inch glass (or graniteware will do) funnel. 



Tin cup. 



Sma// tin pail. 



Flasks. — -Erlenmeyer form. (Fig. 4.) Two sizes, liter and two hundred and 

 fifty cubic centimeters capacity. Bottles may be used, especially if thin glass 

 ones are obtained, such as whisky flasks. 



Fig. 3. — Media cooker. 



Fig. 4. — Erlenmeyer flask. 



Fig. .5. — Wide mouth 

 Blake bottle. 



Test-tubes. — If these are purchased thick walled ones are best and should be 

 made of a kind of glass which will stand continued and high heat. Size, f x 5 

 inches. Homeopathic vials may be used, the straight form, /. e., without necks, 

 are best. The test-tubes are best sterilized in wire baskets which are made for 

 the purpose, but the tin pails enumerated above may be used. 



Petri dishes. These should be about four inches in diameter (Fig. 6). Bot- 

 tles which have large flat surfaces may be used ; such as wide mouth Blake, 8 

 oz. capacity (Fig. 5). 



Glass tumblers. 



APedicine droppers, or glass tubing from which they may be made. 



Thermometer, 0-250°C. 



Potato knife, or case knife. 



Measuring glass, or graduated cylinder. 



Test-tube rack. A wooden block with holes bored in it will do. 



-c 



1 



E *H-.ir:'Jiiriiiir...ii:.;.] ;iiM-i»:'.» B«!liSS 



Fig. 6. — Petri dish. 



O* 



<i 



Fig. 



-Platinum needles, showing part of 

 the handles. 



Microscope and accessories. A microscope magnifying about 500 diameters 

 can be used very satisfactorily in this work, but of course only the larger bacte- 

 ria can be sharply outlined. An oil-immersion objective is a desideratum. A 



