46 



PRACTICAL PHYSIOLOGY. 



[VI. 



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

 alcoholic soUition 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- \dsion spectroscope (fig. 22). 



Fig. 22.— Browning's Strsught- Vision Spectroscopa 



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, h, and F, their position 

 and relation to the colours. ^lake 

 a diagram of the colours, and the 

 dark lines, indicating the latter by 

 their appropriate letters. 



('7.) Fix the spectroscope in a 

 suitable holder, and direct it to a 

 gas-flame, the edge of the flame 

 being towards the sht in the spec- 

 troscope, noting that the spectrum 

 shows no dark Fraunhofer Hnes. 



(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, 



FlO. 23. — Stand for Platinam Wire for 

 Sodium Flame. 



