1868.] 



of Nitrites on the Blood. 



341 



present the same crystalline form, colour, and spectrum, whatever the nitrite 

 which has been employed. The author has obtained compounds of haemo- 

 globin with nitrite of sodium, potassium and silver, and with nitrite of amyl. 

 The methods of preparing them are described, and the results of analysis 

 given ; these show that the amount of a nitrite which adds itself to oxidized 

 haemoglobin varies considerably. 



Having stated the conclusions which he thinks may legitimately be 

 drawn from his investigations, the author concludes by making some obser- 

 vations upon the relation which the compounds of nitrites with haemoglobin 

 bear to the previously known haemoglobin compounds. 



We have hitherto been acquainted with haemoglobin itself, as well as 

 with its O, CO, and compounds. 



These compounds are all isomorphous, and possess almost the same 

 physical characters ; in each of them haemoglobin free from oxygen (i. e. 

 reduced hsemoglobin) has apparently linked to it a molecule of O, CO, or 

 0^ respectively, the stability of the compound being least in the case of 

 the O, and greatest in that of the O^ compound. All these bodies, and 

 preeminently the O compound, are examples of a class of bodies w^hich 

 stand, as it were, on the boundary line which separates chemjcal from 

 physical combination, being examples of the class to which the term mo- 

 lecular compounds " has been given. Like other molecular compounds, their 

 composition varies extraordinarily within certain limits, and is influenced 

 by circumstances and conditions which have no action on chemical com- 

 pounds proper. 



That a body possessing such a very complicated molecular structure as 

 haemoglobin should present numerous points of attachment, as it were, for 

 the linking on of such active condensed bodies as the nitrites is not impro- 

 bable ; nor is it remarkable that, as in the case of other combinations " of 

 a molecular kind," such as the union of salts with their water of crystalHza- 

 tion, of sugar with bases, of albumen with metallic oxides, of the com- 

 pound ammonias with iodine, the amount of the new and more simple 

 body added to the haemoglobin should vary within wide limits. 



Simultaneously with the researches which the author has conducted on 

 the action of nitrites on blood, those now being made by Hoppe Seyler * 

 and Preyer f , although discrepant in many particulars, seem to show that 

 hydrocyanic acid possesses, like nitrites, the power of linking itself to oxi- 

 dized haemoglobin, forming a body which is isomorphous with it, but 

 possessing a different absorption spectrum, and incapable of absorbing 

 oxygen. 



This body appears not to possess the power of ozonizing the atmospheric 

 oxygen, a fact which is strange, as, besides being possessed by the O com- 



* Medicinisch-cliemische Untei'suchungen. Zweiter Heft, 1867, Cyanwasserstoffbamo- 

 globinrerbindungen, p. 201. 



t Die Ursache der Griftigkeit des Cyankalium und der Blausaure, Ton W. Preyer. 

 Yirchow's Ai-chiv, Bd. xl. 21 Hft. Sept. 1867. 



2 K 2 



