﻿s 



lis Dl A iV A U^s' i VEESlT Y 



be added to the aqueous extract before the tincture of guaiac is 

 added, then no blue color will appear at all. Evidently hydro- 

 cyanic acid acts differently from uranium upon this ferment. 



When normal blood is treated with hydrogen peroxide a marked 

 evolution of gas is at once produced. If a solution of uranium 

 (either the acetate, nitrate, or double salt) be added to the blood 

 before the hydrogen peroxide is added, the formation of gas is in 

 no wise hindered. Apparently the reaction takes place exactly the 

 same as in normal blood. When blood is treated with a cyanide 

 and then hydrogen peroxide is added, it is generally stated that 

 no gas at all is produced. As a matter of fact, a very little gas is 

 usually formed, but the reaction is entirely different from that 

 produced by the hydrogen peroxide on normal blood or in the 

 presence of uranium. E\ddently uranium and hydrocyanic acid 

 manifest different properties so far as this reaction is concerned. 



If normal blood be treated with a little tincture of guaiac, a 

 yellowish mixture is obtained, but no blue compound is produced. 

 Addition of a little hydrogen peroxide to the mixture at once causes 

 a great evolution of gas and the development of a deep blue color. 

 The presence of some of the earlier formed yellowish substance 

 gives the whole mixture a deep greenish-blue appearance. If the 

 experiment be repeated in the same manner, but with the addition 

 of a little uranium solution to the blood before the hydrogen perox- 

 ide is added, a profuse evolution of gas and the formation of a deep 

 greenish-blue color is at once observed. The reaction appears to 

 take place exactly as it would if no uranium had been added. 

 When a cyanide is substituted in place of the uranium in the above 

 experiment no gas is formed but the deep greenish-blue color at 

 once makes its appearance. Evident^ in this case, so far as the 

 development of the blue compound is concerned, neither uranium 

 nor the cyanides exercises any noticeable inhibitory activity. The 

 formation of the blue compound in this case seems to be separate 

 and independent from the formation of the methgemoglobin. In- 

 cidentally these experiments show that the ferment in potato peel- 

 ings which causes the guaiac to be oxidized to the blue compound 

 is by no means so resistant as the corresponding ferment in blood, 

 for cyanides stop the action of the former and not that of the 

 latter. 



The general results of these experiments may be summed up 

 in a few words. Cyanides and uranium act differently on some fer- 

 ments, but apparently act similarly (or possibly exert almost no 

 action) on others. Unfortunately these conclusions cannot throw 



