172 BACTERIOLOGY 



and the staining fluid. By this method the nucleus appears 

 stained darker than the rest of the body of the parasite. 



Mannaberg has introduced the following method in order 

 to study the order of events in the life-history of the 

 malaria parasite : The preparation after being dried in air 

 is left for twelve to twenty-four hours in a mixture of equal 

 parts concentrated solution of picric acid and water, to 

 which from 3 to 5 per cent, of glacial acetic acid has been 

 added. It is then deposited in absolute alcohol until com- 

 pletely decolorised, double- stained with alum hsematoxyline 

 solution, and differentiated in 25 per cent, hydrochloric acid 

 in alcohol, and weak ammonia alcohol. The preparations 

 show the red corpuscles and the protoplasm of the leucocytes 

 unstained, but the nuclei of the leucocytes and the plasmodia 

 strongly coloured. 



Malachowski lays the cover-glass preparations in alcoho 

 and stains them in a mixture of equal parts of a 1 per cent, 

 solution of eosine and dilute aqueous solution of borax and 

 methyl blue (-J grm. each of borax and methyl blue in 

 100 c.cm. water), by which method the red corpuscles show 

 yellowish-red, the nuclei of the leucocytes violet, and the 

 plasmodia blue. 



Aldehoff recommends that the blood should be spread 

 out on a cover-glass in the thinnest possible layer, dried in 

 an exsiccator, and subjected for ten or twelve hours to a 

 temperature of 120 C. in the hot-air sterilising chamber. 

 The cover-glass is now left in a concentrated alcoholic solu- 

 tion of eosine for half an hour, or for two or three minutes if 

 warmed at the same time, rinsed in distilled water, double- 

 stained by dipping it several times in a concentrated alco- 

 holic solution of methyl blue, and rinsed repeatedly in 

 water. The blood must be examined immediately after 

 being taken, to avoid mistaking blood-plates for plasmodia. 



Other micro-organisms of the soil. Besides the micro- 



