RESEARCHES ON CHLOROFORM ANESTHESIA 635 



which occur when the vapour of chloroform is inhaled, and 

 under no conceivable circumstances would anything like the 

 amount of 1 per cent, of chloroform ever be found in the blood at 

 the lethal stage of anaesthesia. In 1905 Friedrich Kruger again 

 investigated this point. 1 He states that the precipitate described 

 above is insoluble in water or neutral salt solutions, but is soluble 

 in weak acids or alkalis ; and from both of these the precipitate, 

 as might have been expected, is again thrown down on neutrali- 

 sation. The main interest of Kruger's work, however, lies in 

 the fact that he has described and figured a special absorp- 

 tion spectrum for solutions of this precipitate ; and should 

 this observation be confirmed, it would undoubtedly greatly 

 strengthen the views which are held by Moore and Roaf. Just 

 as Edie has observed, so Kruger found that the chloroform- 

 haemoglobin precipitate was soluble in alkali ; but whereas the 

 former observer states that in solution in sodium carbonate 

 yields the spectrum of alkaline haematin, Kruger describes the 

 spectrum as one showing two bands, a and /9, which occupy 

 a position very similar to the well-known two-banded spectrum 

 of oxy-haemoglobin. The spectra are, however, dissimilar. 



The difference between these and the effect of reducing 

 agents can be seen from the following : 



Effect of dilution Effect of reducing 



with water. agents. 



Disappear together Reduced haemoglobin 

 or a before /3 and haemochromogen 



/3 disappears Reduced 



before a haemoglobin 



Kriiger considers that the effect of reducing agents justifies 

 the conclusion that the chloroform-haemoglobin precipitate 

 consists of a mixture of haematin and haemoglobin or methaemo- 

 globin. Further, that the relation of chloroform to the blood- 

 colouring matter is not that of an indifferent agent, which 

 simply renders haemoglobin insoluble, but that this substance is 

 actually chemically changed, though he has not apparently 

 considered the possibility that there might be a linkage between 

 the drug and this protein. Formanek had already described 

 the spectrum seen by Kruger as that of oxy-haemoglobin, and 

 for the present judgment may be suspended as to the exact 



1 Hofmeister's Beitrage, iii. p. 67, 1903. 



