2QQ BARBER AND TEAGUE. 



Subject No. 2. Canton flannel Broquet mask. 



, „ fPlate No. 1: Prodigiosus absent. 



Saliva taken before exposure jp^^^^ ^^^ ^. prodigiosus absent. 



Cotton from nostrils before exposure Plate No. 1: Prodigiosus absent. 



„ ^^ J. ^ -1 j-^ fPlate No. 1: Prodigiosus absent. 



Cotton from nostrils after exposure <^. . -kt r> -n j- ■ i, 4. 



(Plate No. 2: Prodigiosus absent. 



fPlate No. 1 : Prodigiosus absent. 

 [Plate No. 2: Prodigiosus absent. 

 [Plate No. 1 : Prodigiosus absent. 

 (Plate No. 2: Prodigiosus absent. 



Cotton before mouth after exposure 

 Saliva taken after exposure 



Subject No. 3. Mask of wet gauze 



Saliva taken before exposure 

 Cotton from nostrils before exposure 



[Plate No. 1: Prodigiosus absent. 



[Plate No. 2: Prodigiosus absent. 



[Plate No. 1: Prodigiosus absent. 



[Plate No. 2: Prodigiosus absent. 



^ ^^ . ^ -1 j,^ fPlate No. 1: Prodigiosus absent. 



Cotton from nostrils after exposure -^t^, ^^ -.t n t. j- • i i. 



[Plate No. 2: Prodigiosus absent. 



Cotton before mouth after exposure 



fPlate No. 1 : Prodigiosus present. 



[Plate No. 2: Prodigiosus present. 



„ ,. , , », [Plate No. 1: Prodigiosus absent. 



Saliva taken after exposure It^i ^ t.t r. t-. j- • i_ 



[Plate No. 2 : Prodigiosus absent. 



DISCUSSION OF PROTOCOL NO. 5. 



This experiment was designed to approximate more nearly 

 to the conditions that occurred in Manchuria. It seemed pos- 

 sible that the viscid sputum of pneumonic plague might form 

 larger droplets than the salt solution of our experiments and 

 on that account be unable to pass through the masks. Pre- 

 liminary tests were made by taking prodigiosus bacilli into the 

 mouth and then holding Petri dishes containing solidified agar 

 immediately before the mouth while talking or coughing. It 

 was found that under these conditions prodigiosus bacilli were 

 emitted in too small numbers and too inconstantly for the method 

 to be satisfactory in testing our masks. Swabbing the vocal 

 cords with the bacilli might have given satisfactory results, 

 but this was not tried. Instead of this, it was decided to blow 

 saliva containing prodigiosus bacilli between the lips thus con- 

 verting it into a spray. The droplets of saliva produced in 

 this way apparently passed through the masks as readily as the 

 salt solution droplets from the atomizer. This experiment fur- 

 nishes strong evidence that droplets of sputum from pneumonic- 

 plague patients may be able to pass through the Mukden mask. 



