TRANSMISSION OF THE INFECTION. 141 



Plate B exposed at a distance of 5 centimeters for one minute. Result 

 after forty-eiprht hours: Three colonies. All examined and proved to be 

 a very large bacillus which does not decolorize by Gram. 



Plate C exposed for two minutes at a distance of 5 centimeters. Result 

 after forty-eight hours: Negative for colonies. 



Case 5. — Patient delirious. Plate exposed for two minutes at a distance 

 of 11 centimeters. Patient coughed slightly while plate was exposed. 

 Result after forty-eight hours: Negative for colonies. 



Case 6. — Advanced case with bloody sputum. Temperature 39^ C. 



Plate A exposed for forty seconds at a distance of 11 centimeters. 

 Patient coughed slightly twice during exposure. No visible sputum on agar 

 in plate. Result after forty-eight hours: A single large colony, resembling 

 a colony of the colon bacillus. Microscopically, a very small bacillus 

 which decolorizes by Gram. Planted on an agar slant. This organism 

 was later inoculated in a dose of 0.5 cese subcutaneously into guinea pig 

 No. 5475. The animal remained healthy. 



Plate B exposed for two minutes at a distance of 11 centimeters. No 

 coughing during exposure. Result after forty-eight hours: Three colonies; 

 2 large white colonies which consist of a coccus, the third of a bacillus 

 that morphologically might be the plague bacillus. The colony is small 

 and delicate. This organism decolorizes by Gram's stain. It was planted 

 on an agar slant and later inoculated in a dose of 0.5 oese subcutaneously 

 into guinea pig No. 5487, which remained healthy. 



Case 7. — Plate exposed for a few seconds at a distance of 11 centimeters. 

 Patient coughed three times during the interval. Apparently no sputum 

 touched the medium in the plate. One colony after twenty-four hours. 

 After forty-eight hours no further organisms developed. The single colony 

 consists of a large coccus. 



Case 8. — Plate exposed for one minute at a distance of 11 centimeters. 

 Patient talked slightly while plate was exposed. Result after forty-eight 

 hours: Negative for colonies. 



Case 9. — With much bloody sputum. Plate A exposed for one minute 

 at a distance of 11 centimeters. No coughing during exposure. Result 

 after forty-eight hours: Fifteen colonies; rather heavy and white in appear- 

 ance. None of these suggest plague. Microscopical examination of a 

 number of them reveals a coarse bacillus which does not decolorize by Gram. 



Plate B exposed for two minutes at a distance of 15 centimeters. 

 No coughing. Result after forty-eight hours: A single colony = a large 

 coccus. 



Case 10. — Plate exposed for fifteen minutes in ward horizontally about 

 1 meter from a very sick patient, with much bloody sputum. No coughing 

 during time of exposure. Result after forty-eight hours: Four colonies 

 of moulds and 3 large colonies with yellow centers; evidently not those 

 of the plague bacillus. Microscopically = a coccus. 



Case 11. — Very sick case. Much bloody sputum. Plate exposed for 

 one minute at a distance of 5 centimeters. Patient coughed slightly during 

 exposure. Result after forty-eight hours: Negative for colonies. 



SERIES III. 



Case 1. — Plate exposed for one minute at a distance of 11 centimeters 

 from the mouth. No coughing. Result after forty-eight hours: About 50 

 colonies have developed on the medium. Some of these look macroscopically 



