568 APPLICATION OF METHODS OF BACTERIOLOGY 



duration of the disease was always very much shortened 

 and all recovered. 



Lazaretti^ reports 23 cases of human infection with bac- 

 terium anthracis in which Sclavo's immune serum was 

 employed with recovery in each case. Another patient, 

 suffering from chronic alcoholism and malaria, did not 

 recover. 



Experiments.-^Prepare three cultures of bacterium an- 

 thracis — one upon gelatin, one upon agar-agar, and one upon 

 potato. Allow the gelatin culture to remain at the ordinary 

 temperature of the room, place the agar-agar culture in the 

 incubator, and the potato culture at a temperature not 

 above 18° to 20° C. Prepare cover-slips from each from 

 day to day. What differences are observed? 



Prepare two potato cultures of bacterium anthracis. 

 Place one in the incubator and maintain the other at a 

 temperature of from 18° to 20° C. Examine them each day. 

 Do they develop in the same way? 



From a fresh culture of bacterium anthracis, in which 

 spore-formation is not yet begun (which is the surest source 

 from which to obtain non-spore-beamig anthrax bacteria?), 

 prepare a hanging-drop preparation; also a cover-slip 

 preparation in the usual way and stain it with a strong 

 gentian- violet solution; and another cover-slip preparation 

 which is to be drawn through a flame twelve to fifteen times, 

 stained with aniline gentian-violet, washed in iodine solu- 

 tion and then in water. Examine these microscopically. 

 Do they all present the same appearance? To what are 

 the differences due? 



' Deutsche Vierteljahrssohrift f. offentliche Gesundheitspflege, 1903, 

 Bd. XXXV, Supplement, p. 253. 



