EXAMINATION FOR PLAGUE 479 



80 c.c., calcium carbonate 2 grm. The bacilli retain their vitality 

 and virulence in this for thirteen days (Albrecht-Ghon method). 



( 1 ) Withdraw a little of the fluid from the bubo by means of an 

 antitoxin syringe. Make smears and stain with methylene or 

 thionine blue. Search for short plump bacilli, often in pairs, 

 with polar staining and unstained centres. They are not stained 

 by Gram's method. 



N.B. -There may be a mixture of organisms in the buboes. 



(2) Make agar plates and broth cultures. Incubate the 

 cultures at 25-27 C., not at 37 C. From colonies on the agar 

 plates the organism may be isolated and its cultural and patho- 

 genic characters ascertained. The appearance of the broth 

 cultures, if characteristic, would be very suggestive of plague, 

 but if uniform turbidity develops this may be due to contaminating 

 organisms, e.g. micrococci. 



(3) Inoculate mice, rats, or guinea-pigs subcutaneously with 

 the fluid or with the culture. Some of the animals should be 

 inoculated by the cutaneous method rubbing a little of the 

 material on the shaved abdomen, and also as in (4). Inoculation 

 of rats serves to distinguish the B. pseudo -tuberculosis from the B. 

 pestis. If the animals die, investigate for the Bacillus pestis by 

 staining and culture methods. 



(4) In the pneumonic form, dilute the sputum with a little 

 boiled water, inoculate several agar tubes, and incubate at 

 25-27 C. Examine in two to three days. Also daub the 

 nostrils of a guinea-pig or rat with a brush or pledget of wool 

 dipped in the diluted sputum, avoiding wounding the mucous 

 membrane. Smears of the sputum may also be made, stained, 

 and examined. Gram's method will distinguish the B. pestis 

 from the Streptococcus pneumonice ; the latter stains well by 

 Gram. 



(5) Serum reactions. -Agglutination has been tried, but is not 

 very satisfactory. Dunbar used a method in which the plague 

 bacilli were obtained from a case (and not from a culture), the 

 juice of a bubo or other organ being emulsified in peptone water, 

 and equal quantities of this emulsion and of the patient's serum 

 diluted were mixed so as to form dilutions of the serum of 1 in 200, 

 1 in 400, and 1 in 800. Controls of the plague emulsion with 

 normal serum are also put up. Hanging drops of the mixtures 

 are incubated at 37 C. and examined from time to time. When 



