22 A Ne%v Point of Resemblance in the 



discs or corpuscles, infiltrated with a red colouring matter 

 of very complex constitution called haemoglobin. These red 

 corpuscles take up oxygen while the blood is passing through 

 the capillaries of the lung, the oxygen entering into loose 

 combination with the haemoglobin. As the blood flows in 

 the systemic circulation through all parts of the body, the 

 oxygen is gradually given off*, and enters into definite com- 

 binations with the tissues undergoing disintegration; one 

 of the main ultimate products of the oxidation process being 

 carbonic acid, which is taken up by the blood and carried to 

 the lungs, there to be exchanged for a fresh supply of 

 oxygen. The following passage from Hermann' s Physio- 

 logy (English translation, p. 47) gives shortly what is gener- 

 ally admitted as to the properties of the oxygen contained 

 in the blood, though there is not perfect unanimity on all 

 points, as I will afterwards show: — "As blood when satu- 

 rated with oxygen takes up exactly as much of that gas as 

 corresponds to the amount which its haemoglobin can com- 

 bine with, it follows that all the loosely combined oxygen of 

 the blood is linked to haemoglobin. The oxygen of the blood 

 is given up so readily to oxidizable substances that it has 

 been thought to be present in the form of active oxygen, or 

 ozone O3. The following properties of blood appear to 

 favour this view : — (1.) Both the blood corpuscles and 

 haemoglobin are so-called ' ozone-transferrers' — that is, they 

 possess the power of immediately transferring ozone from 

 substances in which it is present (as turpentine which has 

 been kept for a long time) to readily oxidizable substances 

 (ozone reagents, such as tincture of guaiacum, which be- 

 comes blue by oxidation — Schoenbein, His.); for this reac- 

 tion the presence or absence of oxygen in the blood is of no 

 importance (for instance, it may be saturated with CO). (2.) 

 Blood and haemoglobin can themselves ozonize oxygen, so 

 that in presence of air they can cause guaiacum tincture to 

 become blue (A. Schmidt) ; if the blood itself contains 

 oxygen the presence of air is not necessary ; it is necessary 

 if the blood has been saturated with CO (Kiihne and Scholz). 

 On the activity of its oxygen depends the decomposition of 

 sulphuretted hydrogen by blood. It is therefore very pro- 

 bable that the oxygen naturally contained in blood is present 

 in the form of ozone, or in some similar condition." 



With regard to the first of the properties, viz., the power 

 possessed by haemoglobin of acting as an "ozone -transferrer," 

 there is no room for difference of opinion, that quality 



