TRANSMISSION OF THE INFECTION. 145 



SERIES VI. 



Case 19. — Advanced case, breathing heavily. Temperature 40° C, pulse 

 130. Much bloody sputum, containing large numbers of plague bacilli. 



Plates A and B each exposed for two minutes at a distance of 11 centi- 

 meters. Patient breathing heavily during the exposure. Surface of media 

 in plates wet by the breath. No coughing during time of exposure. 

 Result after forty-eight hours: Plate A, IG colonies; 1 very large colony 

 with irregular borders about 1 centimeter in diameter; (5 heavy white 

 colonies from 3 to 4 millimeters in diameter which do not resemble colonies 

 of the plague bacillus in any way; 2 groups composed respectively of 4 

 and 5 pin-point-sized colonies were examined microscopically and trans- 

 ferred to agar slants. 



Results of cultures from Plate A: 19Al = a bacillus mostly staining 

 as rods, a few taking the bipolar stain; this organism decolorizes by 

 Gram. 19A2 = a similar bacillus to 19 A 1. 19A3=:a large diplococcus. 

 19 A 4 and 5 = a large coccus. 19 A 6 to 9 = a bacillus similar to 19 A 1. 

 Culture 19 A 1 inoculated into mouse No. 13; dose 0.5 cese subcutaneously; 

 animal remained healthy. Cultures 19 A 2, 6, and 9 inoculated by the 

 cutaneous method respectively into guinea pigs Nos. 5463, 5480, and 5481. 

 All of these animals remained healthy. 



Result of Plate B after forty-eight hours: A single small pin-head- 

 sized colony. Evidently the same bacillus as 19 A 1. This organism grows 

 very delicately upon agar. 



Case 20. — Advanced case with bloody sputum. Temperature 40 °C., 

 pulse 134. Enormous numbers of pest bacilli in sputum. Three plates 

 exposed before this patient, each for two minutes at a distance of 15 

 centimeters as follows: 



Plate A. Patient coughed slightly three times during exposure. 

 Result after forty-eight hours: Seven colonies had developed; 1 large 

 colony with uneven edges; 1 very large surface colony and another similar 

 but slightly smaller one. None of these could be colonies of the plague 

 bacillus. The remaining colonies are pin-head in size and were planted 

 on agar-slant-cultures as follows: Cultures 20 A 1 and 4 = a short bacillus 

 which partially decolorizes by Gram's stain. These cultures were later 

 inoculated by the cutaneous method into guinea pigs Nos. 5464 and 5484. 

 Both of these animals remained healthy. Culture 20A2 = a thick bacillus 

 which does not decolorize by Gram's stain. Culture 20A3 = a short 

 bacillus which also does not decolorize. 



Plate B. Patient coughed slightly once during exposure. Result after 

 forty-eight hours: Four colonies developed as follows: Culture 20Bl = a 

 spore-bearing bacillus; culture could not be plague. Cultures 20 B 2 and 

 3 are very large, heavy, white colonies; =a large spore-bearing bacillus 

 which does not decolorize by Gram. Culture 20 B 4=:a plump bacillus 

 which also does not decolorize. 



Plate C. No coughing during exposure. Result after forty-eight hours: 

 Four colonies, 3 large pin-head-sized and 1 pin-point-sized. All transferred 

 to agar-slant-cultures. Results as follows: 20Cl:=a very small bacillus; 

 does not decolorize by Gram. 20C2 = a bipolar staining organism, but 

 does not decolorize at all by Gram. 20C3 = a coccus. Colony on agar, 

 yellow. 20C4 = a bacillus; colony white, rather heavy for plague; mor- 

 phology does not resemble that of the plague bacillus. This organism was 



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