APPARATUS AND METHODS USED IN THIS RESEARCH. 



35 



and is deficient in oxygen. By means of a rotary pump, the air is 

 carried from the chamber and forced through sulphuric acid, which 

 absorbs the water, then through soda lime to remove the carbon dioxide; 

 oxygen is next introduced and when the air returns to the chamber it is 

 free from carbon dioxide and water and contains a normal percentage 

 of nitrogen and oxygen. 



A somewhat more elaborate scheme of the respiration apparatus, 

 giving in considerable detail some of the special connections, may be 

 seen in figure 2. The chamber, C, in which the infant remains, with 



Fig. 2. Detailed scheme of respiration apparatus. 



C, chamber; IF, IF, water jacket; 0, outgoing air-pipe; Z, psychrometer; JV, muffler; P, blower; 

 A, acid trap; B and C, Williams water-absorbers; V\ and Vi, 2-way valves; Di and Z> 2 , 

 carbon-dioxide absorbers; E\ and E%, air-dryers; F, sodium bicarbonate can; J, by-pass; R, 

 valve; K, air moistener; L, oxygen cylinder; I, ingoing air-pipe; S, spirometer; T\ and Ti, 

 thermometers; M, manometer; U, spiral spring; H, pneumograph. 



its surrounding water jacket, W, W, for temperature control, is shown 

 at the upper left-hand corner of the figure. The air leaves the chamber 

 near the right-hand end at 0, and is drawn by the rotary pump over a 

 wet- and dry-bulb psychrometer, Z, which gives the amount of moisture 

 in the air of the chamber. A can, N, filled with dry cotton-batting is 

 also placed in the air-current between the blower and the chamber to 

 act as a muffler. After leaving the exhaust side of the blower, P, the 

 air is forced through an empty glass bottle, A, which serves as a trap 

 should any back pressure take place and sulphuric acid be forced back 

 from the water-absorbing vessels B and C. These latter vessels, which 

 are of peculiar construction, were designed by Dr. H. B. Williams, of 

 the department of physiology of Columbia University, and will here- 

 after be designated as "Williams bottles." The air passes along a pipe 



