THE BLOOD-GASES. 57 



If blood (or a solution of oxyhsemoglobin) be acted upon by adds (e.g., tartaric 

 acid) until it is strongly acid, may be pumped out in considerably less amount, 

 while the formation of C0 2 is not increased. We must, therefore, assume that, 

 during the decomposition of the Hb caused by the acids (p. 33), a decomposition 

 product becomes more highly oxidised by the intense chemical union of the at 

 the moment of its origin (Lothar Meyer, Zuntz, Strassburg). The same phe- 

 nomenon occurs when oxyhaemoglobin is decomposed by boiling. 



37. Is Ozone (0 8 ) Present in Blood? 



On account of the numerous and energetic oxidations whicli occur 

 in connection with the blood, the question has often been raised as to 

 whether the of the blood exists in the form of active (0 3 ), or 

 ozone. Ozone, however, is contained neither in the blood itself 

 (Schonbein) nor in the blood-gases obtained from it. Nevertheless, 

 the red corpuscles (and Hb) have a distinct relation to ozone. 



(1.) Tests for Ozone. Haemoglobin acts as a conveyer of ozone, i.e., it is able to 

 remove the active O of other bodies and to convey or transfer it at once to other 

 easily oxidisable substances, (a.) Turpentine which has been exposed to the air 

 for a long time always contains ozone. The tests for the latter are starch and 

 potassium iodide, the ozone decomposing the iodide when the iodine strikes a blue 

 with the starch. (6.) Freshly-prepared tincture of guaiacum is also rendered blue 

 by ozone. If some tincture of guaiacum be added to turpentine there is no reaction, 

 but on adding a drop of blood a deep blue colour is immediately produced, i.e., 

 blood takes the ozone from the turpentine and conveys it at once to the dissolved 

 guaiacum, which becomes blue (Schonbein, His). It is immaterial whether the 

 Hb contains O or not. 



(2.) It has been asserted also that hsemoglobin acts as an ozone- 

 producer, i.e., that it can convert the ordinary of the air into ozone. 

 Hence the reason why red blood-corpuscles alone render guaiacum 

 blue. This reaction succeeds best when the guaiacum solution is 

 allowed to dry on blotting-paper, and a few drops of blood (diluted 

 5 to 10 times) are poured on it. That the Hb forms ozone from the 

 surrounding 0, is shown by the experiment in which even red blood- 

 corpuscles containing carbonic oxide were found to cause the blue 

 colour (Kiilme and Scholz). 



According to Pfliiger, however, these reactions only occur from 

 decomposition of the Hb, and as a result of this view the blood- 

 corpuscles cannot be regarded as producers of ozone. 



Sulphuretted hydrogen is decomposed by blood (as by ozone itself) into sulphuf 

 and water. Hydric peroxide is decomposed by blood into and water [but this 

 reaction is prevented by the addition of a small amount of hydrocyanic acid 

 (Schonbein)]. Crystallised Hb does not do this, and H 2 O 2 may be cautiously 

 injected into the blood-vessels of animals. This would show that unchanged Hb 

 does not produce ozone. 



Various Forms Of Oxygen. There are three forma of oxygen : (1.) The 



