NO. I AIR AND TUBERCULOSIS — HINSDALE I5 



by rolling the flask in a shallow basin of ice-water, thus distributing 

 the culture in a thin layer over the bottom and sides of the flask. 



These cultures were kept under observation for 20 to 30 days. 

 About 150 cc. of gelatin was used for each experiment. The glass 

 tube (b) of the apparatus used, which served for the entrance of the 

 expired air, was inserted far enough to just impinge on the fluid 

 culture medium in the flask, so that the air produced a slight agita- 

 tion of the fluid in passing through the apparatus. The tube of 

 entrance (b) is provided with a bulb-shaped enlargement which 

 serves to retain any saliva that may flow into the tube. The tube 

 (c) is closed with cotton so as to prevent the entrance of micro- 

 organisms from this side of the apparatus, and a similar cotton plug 

 is inserted in b when the apparatus is not in use. 



Apparatus for Determining the Presence of Bacteria in Expired Breath. 



It was found that the organisms developed in the cultures were 

 all of the same character — a small yellow bacillus, common in labora- 

 tory air. When special precautions were taken to sterilize the appa- 

 ratus with dry heat for an hour previous to introducing the gelatin, 

 besides the subsequent sterilization of the gelatin, the results were 

 negative — no growths developed. If, after standing in the working 

 room for several days, it was found that the culture medium was 

 sterile, the expired breath was then conducted through the apparatus 

 and the culture was kept under observation (for the specified time 

 in the table) at the room temperature. The nature of the organisms 

 that developed in the first two experiments, and the absence of any 

 growth in the others, make it probable that they developed from 

 spores that survived the fractional sterilization of the culture me- 

 dium. It is improbable that they were carried in the expired breath. 

 Dr. Bergey also made a careful examination of the fluid condensed 

 from the expired air with high powers, both in hanging drops and in 

 six dried and stained preparations, but nothing resembling bacteria 

 or epithelium was found. 



The conclusion was reached that there is no evidence of a special 



