TRANSMISSION OF THE INFECTION. 151 



while many attempts at coufjfhiiiK were made. Result after forty-eight 

 hours: Larpe surface K>'owth covering the entire center of the plate, in 

 which are situated about one dozen smaller colonies. Impossible to isolate. 

 Plate discarded. 



Plate G exposed at a distance of 70 centimeters for a few seconds, while 

 patient pave one p:ood coiip:h and made several attempts at couphinp- 

 Result after forty-ei},^ht hours: A number of suspicious-lookinp: colonies 

 present which take the bipolar stain and decolorize by Gram's stain. The 

 organism is evidently the plague bacillus. Surface of plate became wet 

 and plate, therefoz-e, being dangerous to handle was disinfected. 



Plate H exposed at a distance of 70 centimeters. One very good cough 

 during time of exposure. Plate only exposed for a few seconds. Sputum 

 was raised after the cough, but not during the cough. Result after 

 forty-eight hours: Several hundred colonies which look suspicious for 

 plague colonies. The colonies are not isolated, however, but in groups 

 of very fine pin-point colonies and larger heavier colonies, about pin-head 

 in size. A subsequent study of these cultures proves that 2 organisms 

 are present on the plate; 1 a very small short bacillus which only par- 

 tially decolorizes by Gram and whose colony is very delicate on agar and 

 the other a bipolar-staining organism which entirely decolorizes by Gram. 

 The latter organism was inoculated by the cutaneous method into guinea 

 pigs Nos. 5310 and 5448, both of which died of typical plague infection, 

 the former eight days after infection, the latter three days after infection. 

 Two of the cultures of the organism which formed very delicate colonies 

 on agar and which only partially decolorized by Gram's stain, were in- 

 oculated into guinea pigs Nos. 5313 and 5317, both of which remained 

 healthy. 



Plate I exposed at a distance of about 85 centimeters from the mouth 

 for one and one-half minutes. Two good coughs during time of exposure. 

 No visible sputum on plate. Result after forty-eight hours: Several hun- 

 dred colonies that look suspicious of the plague bacillus. Colonies in small 

 groups. Four of these groups planted on agar. Culture 32 I 1 did not 

 develop; cultures 32 12, 3, and 4 all revealed a bipolar organism which 

 decolorized by Gram's stain; three of these cultures were later inoculated 

 into guinea pigs Nos. 5303, 5449, and 5450, all of which died of typical 

 plague infection four days, six days, and eight days, respectively, after 

 inoculation. 



Plate J. Patient coughed during exposure. Small amount of sputum 

 touched the plate. Plate, therefore, discarded. 



SERIES XI. 



Case 33. — Much bloody sputum which contained innumerable plague 

 bacilli. Temperature 39°. 8 C. Physical examination shows tubular mod- 

 ification of breath sound and signs of early oedema of the lungs. 



Plate A exposed at a distance of about So centimeters. Patient gave 

 five coughs during time of exposure. Plate then closed. Result after forty- 

 eight hours: About 100 colonies scattered over the surface of the plate. 

 Many look like plague. A number of these transferred to agar-slant- 

 cultures. Subsequent study of these cultures shows that the majority 

 consists of a bacillus which takes a bipolar stain and is completely decolor- 

 ized by Gram's stain. Three of these cultures were later inoculated into 

 guinea pigs Nos. 5302, 5451, and 5452 by the cutaneous method; all of these 



