118 HAEMATOLIN. HAEMOCHROMOGEN. [BOOK 1. 



A second iron-free derivative from haematiii has been obtained by 

 Hoppe-Seyler, which differs from haeinatoporphyrin in being nearly in- 

 soluble in sulphuric acid and in caustic leys. To it he attaches the pro- 

 visional name of Haematolin, and the formula CegH^NgOy 1 , 



Haemochromogen. 



According to Hoppe-Seyler when reduced haemoglobin is decom- 

 posed in the absence of oxygen, instead of haematin, there is produced 

 a body to which he gives the name of haemochromogen, whose 

 solution presents a beautiful purple colour, but which is converted 

 almost instantly into haematin when oxygen comes in contact with it. 

 This body when in alkaline solution is, as proved by the most careful 

 measurement of its absorption bands, identical with the so-called 

 reduced haematin of Stokes. 



The following are the two methods which at different times 

 Hoppe-Seyler has employed for the preparation of haemochromogen: 



I. In the Woulffs bottle A (see annexed woodcut) hydrogen is evolved 

 by the action of dilute hydrochloric acid upon zinc, and the gas is washed 

 by passing through the wash-bottle (7, which contains dilute solution of 

 caustic soda. In order that the acid which is to act upon the zinc shall be 

 free from oxygen, a piece of zinc is placed in the beaker B which contains 

 the acid. 



First of all having opened the clips b and &', by aspirating at the a end 

 of the wash-bottle, a sufficient quantity of acid is made to flow out of the 

 beaker B to fill the tube f and then enter A where it evolves hydrogen, 

 which gradually expels all the air from the apparatus. The clip b is 

 then closed. After gas has been passing for about half an hour the 

 bulb-apparatus DEF is attached to the wash-bottle in the manner 

 represented in the diagram. This bulb-apparatus contains in the 

 division F concentrated solution of oxy-haemoglobin, and in the 

 division D alcoholic solution of sulphuric acid or potassium hydrate, or 

 instead of these an aqueous solution of potassium hydrate. A stream 

 of gas is now again allowed to pass through the apparatus by opening the 

 clip b and raising the vessel B so as to allow a fresh quantity of dilute acid 

 to enter A and act upon the zinc which it contains. (If A happens to be 

 already full, the solution of ZnCl 2 which it contained might be removed by 

 depressing the vessel B and allowing it to be on a lower level than A. 

 The vessol A having been thus more or less completely emptied, and 

 the clip b closed, a fresh stock of dilute acid may be placed in BA, 

 and everything is ready for recommencing.) After a stream of H has 

 passed through the whole apparatus, including the bulbs, for some 

 considerable time (2 or 3 hours), the bulb-apparatus is sealed in a blowpipe 

 flame at d and at e. By means of the spectroscope the observer determines 



1 The whole description of haematin and its derivatives is abridged from the 

 memoirs of Hoppe-Seyler, of which the most important relating to this subject 

 is the one entitled "Das Hamatin," under the general heading of "Beitrage zur 

 Kenntniss des Blutes des Menschen und der Wirbelthiere." Hoppe-Seyler's Med. 

 Cliem. Untersuchungen, Heft iv. (1871) p. 523. See also " XJeber die Zersetzungen der 

 Hamoglobine." Ibid, p. 377385. 



