2522 Journal of Applied Microscopy 



phyte. Sketch under low power showing the sporophyte with capsule and sper- 

 culum, and the expansion at the top of the pseudopodia into which the foot fits. 



10. Draw some of the nonsexual spores under high power. 



11. From prepared slides make a drawing of a longitudinal section of the 

 sporophyte, showing all the details of the structure. 



12. Study and draw an apical cell from a branch of the gametophyte, from 

 a prepared slide. John H. Schaffner. 

 Ohio State University. 



Bacteriology for High Schools. 



Copyrighted. 



V. 



MICROSCOPICAL EXAMINATION OF BACTERIA— Continued. 



The bacteria are very widely distributed in nature and are found in practically 

 all parts of the earth, except in the air in mid-ocean and in that on the tops of the 

 highest mountains. By means of the potato culture already described it would be 

 possible to determine facts in regard to their variety and distribution. It will, 

 however, be found more satisfactory to use for this purpose, not potato cultures, 

 but gelatine cultures. 



Preparation of Gelatine CuHitre Medium. This method is essentially a beef 

 broth, or bouillon, to which enough gelatine has been added to cause it to 

 solidify. 



A teaspoonful of extract of beef such as Leibig's or Armour's is added to a 

 pint of water which has been placed in the inner vessel of a double walled cooker. 

 In case the extract of beef is not readily obtainable one-half pound of lean beef, 

 as round or shoulder steak, is purchased and cut up fine (minced) and put to 

 soak in a pint of water over night in a cool place. In the morning the juice is 

 squeezed out by straining through a cloth and enough water added, if necessary, 

 to make a pint. This meat juice is now placed in the cooker as above. It 

 ought, perhaps, to be stated that the latter method is always the best, but that 

 the other is much easier to prepare, is sufficiently good and is, therefore, 

 given first. 



To the meat juice is now added two ounces of gelatine. One of the gela- 

 tines for sale at all of the grocery stores will do, although it is best to have a 

 sheet gelatine. This amount is intended to make a 10 to 12 per cent, gelatine. 

 The water in the outer dish is now brought to a boil and the heat continued 

 until the gelatine is all in solution. The gelatine is very acid and must be neu- 

 tralized. It is best done at this point. It is most conveniently done by adding 

 ordinary baking soda or saleratus. This should be added in very small amounts 

 and after such addition a strip of red litmus paper should be dipped into the 

 medium. At first the paper will not be changed in color, but as the additions 

 continue a point will be reached where the red paper will be turned a faint blue. 

 If it is tested at this point with a piece of blue paper the color will not be 



