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PROF. T. CARNELLEF, MR. J. S. HALDANE, AND DR. A. M. ANDERSON 
be expected that a large number of bacteria would be given off from bed clothes when 
shaken. * 
In connexion with this subject some of our observations in jute mills are of interest. 
In each of three large rooms examined in different mills the ah' was loaded with jute 
fibres, the amount of physical disturbance being very great in each. In the ah of the 
first, 4 bacteria per litre were found ; in that of the second about 586 bacteria per 
litre were found, and 14 moulds; in that of the third about 12 bacteria and 248 
moulds (see pp. 83-84). The latter observation was repeated with a similar result five 
weeks later. These observations show how small the influence of physical disturbance 
may be unless combined with other factors. 
It is evident that the micro-organisms present in the air of an inhabited room may 
conceivably come (1) from the air-passages of the persons present, or (2) from their 
clothes and skin, or (3) may have been previously present in the room. We shall 
consider in succession these possible sources. 
1. The air-passages might possibly give off micro-organisms in the breath. As 
regards this point we made the following direct experiments. A piece of very wide 
glass tubing, A (see diagram), of about 20 centims. length, was fitted at each end with 
a cap of india-rubber sheeting similar to the cap of the tube of Hesse's apparatus. 
Through a hole in one of the caps the end of an ordinary Hesse’s tube, B, was passed, 
so that the part of the latter covered by its cap was completely inside the piece of 
wide tubing. Through another hole at the same end of the wide tube A there passed 
a piece of narrow glass tubing D. The cap at the other end of the wide tube was 
also perforated by a very short piece of glass tubing of medium width, E. The tube A 
having been washed thoroughly with 1 per cent, corrosive sublimate solution and allowed 
to dry, the cap of the tube B was cautiously removed, and the apparatus arranged in 
the position described. The observer expired through the tube E, inspiring through his 
nose, while immediately afterwards the aspirator attached to C was set in motion. The 
object of D was to allow of the free escape of the breath not sucked into B. In order 
crystallisation of a supei’saturated solution of a salt is set up by dust particles dropping into tbe solution. 
The fact that the crystals were larger when there were few present doubtless depended on their having 
more jelly from which to draw during their formation. The whole phenomenon suggests a possible 
method for determining the number and relative rate of settling of the dust particles in given volumes of 
air. As the data given above tend to show, there is probably a rough correspondence, under similar 
conditions, between the number of solid particles suspended in air and the number of micro-organisms. 
* This observation gives one a vivid idea of the manner in which an infectious disease may spread 
through a ward. 
