32 



CHEMICAL PHYSIOLOGY. 



the glass plates being exactly 1 cm. apart (Fig. 6, D). Study 

 this instrument (Hoppe-Seyler). 



8. Hsematoscope. By means of this instrument the depth of 

 the stratum of fluid to be investigated can be varied, and the 

 variation of the spectrum, with the strength of the solution, or 

 the thickness of the stratum through which the light passes, at 

 once determined (Hermann). Study this instrument. 



Red. Orange. Yellow. Green. Blue. 



g. 4 Spectra of Haemoglobin and its compounds. 1, Oxy-haamoglobin 

 0-8 per cent.; 2, oxy-haemoglobin, 0'18 per cent.; 3, carbonic oxide 

 haemoglobin ; 4, reduced haemoglobin. 



9. II. Reduced Haemoglobin. 



(a.) To a solution of oxy-hsemoglobin showing two well- 

 defined absorption bands, add a few drops of ammonium 

 sulphide, and warm gently, when the solution becomes 

 purplish or claret-coloured. 



(b.) Study the spectrum, and note that the two absorption 

 bands of oxy-haemoglobin are replaced by one absorption 

 band between D and E, not so deeply shaded, and with its 

 edges less defined (Fig. 4, 4). By shaking the solution very 



