134 STRONG. 



The tails of the bandage were tied one below the ear behind the 

 neck, one above the ear, and the third above the head as a jaw 

 bandage. The spaces on each side of the nostrils between the 

 mask and the cheeks were plugged with cotton-wool. The whole 

 mask was then covered with another piece of gauze in which 

 openings for the eyes were made and the ends cut into four 

 tails and tied behind the head and neck. (See Plate V.) This 

 gauze served to keep the mask in place and to hold it securely 

 against the face. While this form of mask appeared during 

 the epidemic to be efficacious in preventing the wearer from con- 

 tracting plague infection from a pneumonic-plague patient, two 

 preliminary experiments performed in this laboratory by Teague, 

 Barber, and the writer - have shown that this type of mask is 

 not perfectly bacteria-proof. Since, however, as it has already 

 been pointed out, we were frequently for hours at a time in close 

 contact with coughing pneumonic-plague patients and remained 

 entirely healthy, it appears that, during an epidemic, this form 

 of mask is, at least, usually safe for practical purposes, and 

 that while the gauze and cotton comprising the mask may not 

 intercept bacteria, which are suspended and sprayed in a fine 

 vapor in salt solution or even in saliva, they nevertheless usually 

 intercept the fine droplets of sputum emitted, for example, by 

 the cough of pneumonic-plague patients.^ However, the very 

 careful and complete experiments of Barber and Teague, for 

 which they deserve entire credit,* throw considerable doubt upon 

 the question of the degree of protection that would be afforded by 

 this mask during a pneumonic-plague epidemic. These authors 

 also demonstrate that the Broquet type of mask is more efficient. 



" Report of the International Plague Conference held at Mukden, April, 

 1911. Manila (1912), 394. 



* The droplets of mucus emitted from coughing pneumonic-plague patients 

 are evidently much larger and heavier than the majority of those which 

 are disseminated from an artificial spray of any kind and particularly is 

 this true in the case of those where a force-pump is employed. Where 

 the bacteria are suspended in saline solution and sprayed with a fine 

 spray, the particles are always very much finer than those emitted from 

 coughing individuals and have a much greater power of permeability. 

 See Kirstein, Ztschr. f. Hyg. u. Infectionskrankh. (1900), 35, 123; 

 Hutchinson, ibid. (1901), 36, 223. Laschtschenko states, ibid. (1899), 

 30, 132, the mucus droplets are also not so easily transportable as the 

 particles from a spray. According to Heymann, ibid. (1899), 30, 139; 

 (1901), 38, 21, the smallest droplets emitted by coughing tuberculous 

 patients have a diameter of not less than 30 fj-f^. 



^ See XII, p. 255 of this report. 



