Myxomycetes and Schizophytes 155 



condition, they form a scum on the surface of the water. Usually, 

 the first to appear is a somewhat rod-shaped form, the Bacterium 

 termo of the older texts. Spirillum and Coccus forms often ap- 

 pear later. 



Fine preparations may be obtained by inoculating a mouse with 

 Anthrax, or some other form, and then cutting paraffin sections of 

 favorable organs. For making mounts of a dangerous form like 

 Anthrax, secure properly fixed material from a bacteriologist. 

 Gentian-violet with a faint Bismarck brown or with light green for a 

 background makes a good combination. The following schedule 

 gives good results with Anthrax and many other bacteria: 



1. Gentian- violet, 5 minutes. 



2. Rinse in water a few seconds. 



3. Gram's solution (iodine 1 g., potassium iodide 2 g., water 300 c.c.) 

 until the color is almost or quite black; this will generally require 

 1 or 2 minutes. 



4. 95 per cent alcohol until the color has nearly disappeared. 



5. Rinse in water and examine. If the bacteria are well stained, a 

 counter-stain may be added. 



6. Light green or erythrosin, 5 seconds; or Bismarck brown, 5 or 10 

 seconds. 



7. 95 and 100 per cent alcohol, dehydrating as rapidly as possible. Not 

 more than 5 or 10 seconds can usually be allowed. 



8. Absolute alcohol and xylol, equal parts, 3 or 4 seconds. 



9. Xylol, 1 to 5 minutes. 

 10. Balsam. 



The following rapid method gives fairly good results : 



1. Place on a clean cover a drop of water containing the bacteria and 

 dry completely in a flame or on a hot plate. 



2. Stain 2 to 5 minutes in gentian-violet or methyl violet. 



3. Rinse quickly in water. 



4. Dip into 95 per cent alcohol to reduce the stain. 



5. Remove most of the alcohol by touching a corner of the cover with 

 filter paper and then dry completely by passing through a flame. 



6. Mount in balsam. 



Leptothrix may often be obtained by scraping the inside of the 

 cheek. Beggiatoa, one of the sulphur bacteria, with oscillating 



