t m of the blood receiver prevents tie Wood from frothing over into the P ,,n,p ; and ,i the action I 



" * '" " ""' be immediately allayed by pouring a few drops of warm water on to th,- tul>r IF) 



ire thereby dr.ven back into the receiver, and the pump is never fouled. The tap (ui is M mui.ipuUt.- 

 lt the- gases only, ami not the water which condenses in the reservoir (.,). are .Ir.v,-,, th-- eudioni 

 ,e water is returned back into the blood receiver. Three to four exhaust,,,,,-, .m- -..Undent to rxtr.u t ,11 tl,,- 

 . I from about 10 grammes of blood. The gases are estimated by the potash and pvrogalli< a< i.l mrtl.od The 

 - liometer tubes are surrounded with a water jacket to keep the temperature constant In rescar. I, work 

 hultaneous samples arc drawn from the arterial system, and from the vein leaving the organ th.- met lU 

 wrhich is under investigation. The sample of blood can be drawn conveniently into small Lull* ho 

 ,t i<> cubic centimetres, which have been previously washed out with oil ; from thence th.- bloo.1 ,, 



rred to the blood receiver. No loss of gas has been found to occur in using this mrthod 

 With tins pump four complete analyses can be done in two hours. 

 I'ici,- Hill and Narbarro on " The Exchange of Blood Gases in Brain and Muscle " (Journal u/ /'/,t 





791 792 



1 Muscle Chamber for use in conjunction with gas pump, Fig. 790 



each 



17 6 



In addition to the blood receiver, a muscle chamber can be supplied with the pump. 



I his chamber is closed at the upper end by a rubber cork, and the cork is surrounded by a mercury cup. 



short piece of glass tubing (A) passes through the cork, and this is fitted with a piece of pressure tubing and 



dip. Two insulated platinum wires (B) and (c) also pass through the cork one of these ends in a 



i"k. From this hook the frog muscle preparation is suspended. At the lower end of the muscle is attached 



i bucket (n), fitted with a vertical rod (E). From the wire (c) passes a piece of fine wire, which is tied 



nn<l the lower end of the muscle. After fitting the muscle preparation in position, the muscle chamlx-r is 



'st attached to the tube (E) of the gas pump, and then filled with mercury up to the top of the tube (A). 



uring this operation the vertical rod fixed to the iron bucket prevents the muscle from floating up to the top 



the mercury. The screw clip on (A) is next closed, and a vacuum made in the muscle chamber. The bucket 



'ft full of mercury, and hangs as a weight on the muscle. The muscle can be excited. 



')2 Waller's Apparatus for the analysis of expired air, on polished mahogany stand 



eac.i 



3 10 



CHEMICAL AND SCIENTIFIC APPARATUS AND PURE CHEMICALS- 



165 



