3S 



THE COMPOSITION OF EXPIRED AIR, 



minations in the table, the mouth was well rinsed in a weak solution of formalin or with wartn water. 

 A reduction of 1.2 Mg. of O. per litre in the 23d from the amount required for the fluid collected 

 the half an hour before, seems to have resulted from the use of the antiseptic mouth wash, in others a 

 still greater reduction was brought about by simjjly rinsing the mouth several limes with warm water. 

 Several efforts were made to obtain evidence as to the chemical nature of the condensed fluid 

 collected from my own breath. Eighty (80) litres of expired air were conducted through 50 c. c. of 

 a one per cent, solution of oxalic acid in ten minutes. 'I'his fluid gave a decided yellowish-brown 

 color with i. c. c. of Nessler's reagent, showing at least five times as much ammonia as was present 

 in the distilled water used to make the oxalic acid solution. The fluid condensed from exhaled 

 breath, obtained by conducting the breath through a condensing apparatus laid in ice, was tested 

 with the following reagents for the presence of a volatile organic alkaloid : AuClj, PtCl^, 

 Ammon. Molybdate, Ag NO3 ; reaction negative. Nessler's reagent produced a yellow color, and 

 a few drops of a 10 per cent, solution of HgClj with a few drops of a 10 per cent, solution of 

 KI also gave a yellow color. 



The results of the tests, though few in number, give no evidence of the presence of expira- 

 tory products other than those indicated by the determinations of ammonia, and the reducing 

 power on solution of permanganate of potash. 



III. — Experiments with fluid condensed from the air of a large surgical ward in the University 



Hospital, with and without filtration of the air. 



Several efforts were made to collect moisture from the 

 air of a crowded surgical ward of the Hospital by means of 

 a large glass funnel, sealed at the neck and filled with ice. 

 A small beaker was placed beneath the funnel to collect 

 any moisture condensing on its exterior. This method 

 proved unsuccessful, and was abandoned. An apparatus, 

 shown in Fig, 3, and arranged as shown in Fig. 4, was 

 placed on a mantel over an unused open fire-place at one 

 end of the ward. 



Description of the apparatus used to condense the 

 moisture in the air of the hos])ilal ward : 



Fig. 3 represents the condenser, consisting of a, a small 

 glass receptacle eleven centimetres in height and three 

 centimetres in diameter at its widest part, and having a 

 capacity of 50 c. c. This receptacle has two openings, the 

 one at the top being closed with a closely fitting, hollow, 

 glass stopper ; the second opening consists of a glass tube 

 coming obliquely from the expanded portion near the top, 

 and at a distance of three centimetres bends upward along 

 the side of the receptacle. This serves as the exit tube to 

 the receptacle, while the air enters through the hollow glass 

 slopper closing the other opening. Each of the tubes has an internal diameter of four millimetres. The 

 spiral portion of the condenser consists of a piece of block- tin tubing, b, three metres in length, 

 and five millimetres in internal diameter. This is connected with the entrance tube of the recep- 

 tacle by means of a short piece of rubber tubing, and with the dust filter by a longer piece of 

 rubber tubing. The exit tube of the recei)tacle has a piece of glass tubing, thirty centimetres in 

 length, and five centimetres in internal diameter, fused to its end. This is bent at right angles 

 near its upper extremity, and connected with the gas meter by means of a piece of rubber tubing. 



Fig. 4, represents the apjiaratus as arranged in the hospital ward, a represents an inverted 

 bell-jar with the condenser packed in ice. The bell-jar is supported by an iron tripod, b. The 

 dust filter, consisting of a glass tube loosely ])acked with asbestos, is represented at c, and 

 is attached to a stative by means of a clamp, while e represents the gas meter, and / the water 

 faucet in the lavatory. The meter is connected with the faucet by means of a long piece of block- 



Fir.. 3. — Condenser of apparatus shown 

 in Fig. 4. (X 5.) 



