August 1 6, 1888] 



NATURE 



3S1 



Fie, 2 



Fig. 5 



Description of Figures. 



3. — Views of a gas pump constructed for the purpose of extracting and collecting the gasss of the blood and suitable for the physiological 

 table. These views have been correctly drawn on the scale of 1 to 10 by my friend the Rev. A. Hanns Geyer.* Fig. i, front view : a, 



Figs. 1, 2, and 3. 

 lecture 



glass bulb connected by horizontal glass tube with bulb b ; this tuba guarded by stopcock c. By elevating u, a is filled with mercury, stopcock of 

 delivery tube Q is closed, and b is lowered ; a is thus exhausted and air is drawn into it by tubes e, connected by G with drying apparatus and blood 

 chamber. 1, permanent barometer ; j, barometer gauge tube connected with part of instrument to be exhausted. Both 1 and j dip into mercury 

 trough seen below ; s, a glass float to prevent mercury from running into drying apparatus when b is raised. After a and the drying apparatus and 

 the blood chamber have been well exhausted, b is raised and mercury may be allowed to pass up d, and then the apparatus acts as a Sprengel pump 

 by the three tubes e. Fig. 2, side v.ew of apparatus: sam: references. Fir. 3, drying apparatus, placed on a shelf at the top of the pump, 

 consisting of h, tubes containing solid phosphoric acid, and U-tube p, seen in Fig. 2, containing suIphurL acid. The tube k passes to receiver. In the 

 drawing it is seen to be connected with an apparatus suitable for projecting the spactrun of oxy-haemoglobin by lime or electris light on screen; 

 then exhausting the blood of oxygen and showing the spectrum of reduced haemoglobin, l and vi, froth chambers with traps; n, parallel-sided 

 chamber for blood ; o, stopcock. The whole prnip is modelled on one 1 obtained about ten years ago from Messrs. Mawson and Swan, of 

 Newcastle, but it has been much altered and ad led to so as to make it suitable for physiological demonstration. It is evident that the gases can be 

 readily obtained for analysis by driving out of a by delivery tube q. A rough demonstration of the gises cin be made in from five to ten minutes. 



1 The pump can be obtained from Mr. W. Potter, glass-bbwer, Physical and Physiological Laboratories, University of Glasgow, who will give 

 information as to cost. 



