4 6 



PRACTICAL PHYSIOLOGY. 



[VI. 



4. Ozone Test for Haemoglobin. Mix some freshly-prepared 

 alcoholic solution of guaiacum with ozonic ether; the mixture 

 becomes turbid, and on adding even a dilute solution of haemo- 

 globin, a blue colour results, due to oxidation of the resin by the 

 ozone liberated from the ozonic ether by the haemoglobin. 



5. Spectroscopic Examination of Blood. Use a small Brown- 

 ing's straight- vision spectroscope (fig. 22). 



Flo. 22. Browning's Straight- Vision Spectroscope 



Preliminary. Observe the solar spectrum by placing the 

 spectroscope before the eye, and directing it to bright daylight. 

 Note the spectrum from the red to the violet end, with the inter- 

 mediate colours, and focus particularly the dark Fraunhofer's lines, 



known as D in the yellow, E in 

 the green, b, and F, their position 

 and relation to the colours. Make 

 a diagram of the colours, and the 

 dark lines, indicating the latter by 

 their appropriate letters. 



(ft.) Fix the spectroscope in a 

 suitable holder, and direct it to a 

 gas-flame, the edge of the flame 

 being towards the slit in the spec- 

 troscope, noting that the spectrum 

 shows no dark Fraunhofer lines. 



(6.) Fuse a piece of platinum 

 wire in a glass tube, and make a 

 loop at the free end of the wire 

 (fig. 23). Dip the platinum wire 

 in water and then in common 

 salt, and burn the salt in the gas- 

 flame, having previously directed the spectroscope towards the gas- 

 flame, and so arranged the latter that it is seen edge-on. Note "the 

 position of the bright yellow sodium line in the position of the 

 line D. 



Fro. 23. Stand for Platinum Wire for 

 Sodium Flame. 



