340 



Dr. A. Gam gee on the Action 



[May 7, 



tions have been taken to exclude atmospheric air. The continued action 

 of the reducing-solution then leads to the reduction of the blood-colouring- 

 matter, which when shaken with air again yields the perfectly normal 

 spectrum of blood. It would therefore appear that when nitrites act upon 

 the blood- colouring-matter they do not decompose it, nor thrust out or 

 remove the loose oxygen with which it is combined. 



II. The author then describes a series of experiments instituted with the 

 object of determining whether blood which has been acted upon by nitrites 

 has lost its power of combining with the atmospheric oxygen. The appa- 

 ratus and methods used are described, and it is shown that the amount of 

 oxygen which nitrite-blood absorbs is much smaller than that absorbed by 

 normal blood. 



III. In the next series of experiments the author made use of carbonic 

 oxide gas as a reagent to indicate whether after the action of nitrites the 

 loose oxygen of the colouring-matter is still capable of expulsion by CO. 

 With this object the blood was arterialized by agitation with air and treated 

 with a solution of a nitrite. After some time it was brought in contact 

 with a measured volume of pure carbonic oxide ; after being v/ell agitated 

 and allowed to remain in contact with it for some time, the gas was re- 

 moved and analyzed. It was found in these experiments that, after the 

 action of nitrites, the loose oxygen of the blood-colouring-matter (which 

 the observations mentioned under I. had been shown to be neither expelled 

 nor taken possession of by the nitrite) v/as so locked up as to be irre- 

 moveable by carbonic oxide. 



IV. The methods which have been employed by other observers for re- 

 moving the gases from the blood are then examined, and the author de- 

 scribes the way in which he employed Sprengel's mercurial aspirator to 

 effect the object which he had in view. He shows that with this instru- 

 ment and following his method, the gases of the blood may be separated by 

 boiling in vacuo during twenty-five or thirty minutes. 



The gases of both normal blood and blood treated with nitrites were 

 boiled out in vacuo, their amount estimated, and their composition deter- 

 mined. It is shown that when blood has been acted upon by a nitrite, the 

 amount of oxygen which can be removed by ebullition in a very perfect 

 vacuum is immensely dimiDished, the greatest difference being perceived 

 when the nitrite had been in contact with the blood during the longest 

 period of time. 



V. Although blood which has been acted upon by nitrites has, to a 

 great extent, lost its power of absorbing oxygen, it still retains the property 

 which norm.al blood possesses of ozonizing the atmospheric oxygen. Ni- 

 trite-blood reacts with guaiacum paper exactly like normal blood, and when 

 added to a solution of peroxide of hydrogen, it causes an evolution of oxygen. 



VI. The changes in the optical properties of blood are shown to be due 

 to the formation of compounds of the nitrite used with oxidized heemo- 

 globin ; these compounds, with the exception of that with nitrite of silver. 



