2208 Journal of Applied Microscopy 



Jq inch is about 20 per cent, cheaper than the usual yV inch and is satisfac- 

 tory for all ordinary bacteriological work. A substage condenser and iris dia- 

 phragm are necessary if an oil-immersion objective is used. 



Slides and cover-glasses. Only a very thin cover-glass can be used. A glass 

 0.17 mm. thick or a No. 2 Bausch & Lomb are the thickest that can be used, since 

 with the thicker ones it is impossible to use the oil-immersion objective. 



• Platinum needles. Two inches of No. 27 platinum wire should be fused into 

 glass rods for handles (Fig. 7). These needles are for handling the bacteria 

 and will be much used. It is probable, however, that in this course all the work 

 required can be done with ordinary " hat pins." 



Gummed paper. For labels or a wax pencil made for writing on glass may 



be used. 



CHEMICALS. 



Extract of beef. Leibig's or similar grade. 



Peptone. The dry form. 



Sodium chloride. Common table salt. 



Soda. Baking soda or saleratus. 



Gelatin. The gold label sheet gelatin is best, but the commercial article, 

 such as Knox, can be used. 



Dextrose, or grape sugar. 



Absorbent cotton. 



Cotton wool. A good grade of cotton free as possible from foreign matter. 



Litmus paper. Blue and red. 



Filter paper. Either in sheets or circular, of a size to fit the funnel. 



Anilin dyes. A saturated alcoholic solution of fuchsin or methylen blue. 



Corrosive sublimate tablets. 



Canada balsam. Dissolved in xylene (xylol) and about the consistency of oil. 



Immersion oil. This will probably be supplied with the oil-immersion lens 

 and will not be needed except for use with such an objective. 



A more complete list of bacteriological apparatus will be furnished by any of 

 the dealers. In making out any list it is desirable to have a catalogue issued 

 by such firms as: Bausch & Lomb Optical Co., Rochester, N. Y.; Eimer & 

 Amend, New York City ; Leitz, Chicago, 111.; Richards & Co., Chicago, 111. 



W. D. Frost, 

 Bacteriological Laboratories, University of Wisconsin. E. G. HASTINGS. 



Improved Hot Air and Steam Sterilizers. — If one has access to a 

 kitchen oven after cooking or baking, the temperature is quite high enough for 

 sterilizing dishes, test tubes, pipettes, flasks, cotton wool, etc. Cotton wool 

 should be put inside a beaker, and when it is slightly scorched the articles may 

 be considered sterile, or, if a thermometer is used, when they have been ex- 

 posed for one hour to a temperature of 150° C. For a steam sterilizer for 

 culture media nothing more is necessary than an ordinary medium-sized kitchen 

 pan half full of water boiled over a ring gas-burner, and provided with a potato- 

 steamer, the sides of which may be covered with ordinary felt in order to con- 

 serve heat as much as possible, and the lid, if close fitting, should have three or 

 four small holes made in it, so that there may be direct circulation of steam. — 

 four. State Med., 11 : 2. 



