1003.] On the Optical Activity of Haemoglobin and Globin, 379 



The polarimeter employed in these observations was a magnificent 

 Lippich's " Halbschatten-Polarimeter," with tripartite field of vision, 

 made by Schmidt and Haensch, of Berlin, and belonging to the Davy- 

 Faraday Laboratory of the Eoyal Institution of Great Britain. 



The Haemoglobin Employed* 



The solutions of haemoglobin employed for the determinations of 

 which the results will be given below, were prepared with oxy-hsemo- 

 globin of remarkable purity which had been obtained from the blood 

 of the horse by following the best of the methods (the third method) 

 described by ZinofTsky.f 



Two preparations of haemoglobin made on a large scale and at the 

 interval of some months one of the other were employed. The 

 preparation employed to make the solution of Oxy-h hemoglobin had 

 been crystallised three times, the product of each successive crystalli- 

 sation having been many times washed with ice-cold distilled water 

 of which the purity was controlled by determining its electrical 

 resistance. This solution contained 2*446 grammes of heemoglobin in 

 100 c.c. For polarimetric observations this solution was diluted with 

 an equal volume of distilled water, the dilute solution examined con- 

 taining, therefore, 1*223 gramme of oxy-hsemoglobin in 100 c.c. 



The preparation employed to make the solution of CO-haemoglobin 

 had been crystallised four times. The crystals of each successive 

 crystallisation had been subjected to washing with pure distilled 

 water as stated above, the solution of the washed crystals of the 

 fourth crystallisation having been saturated with CO. This solution 

 contained 1*84 grammes of dry CO-haemoglobin. For polarimetric 

 measurement this solution was diluted with an equal volume of 

 distilled water ; the dilute solution contained, therefore, 0*92 gramme 

 of CO-haemoglobin in 100 c.c. 



Hwrnoglohin, whether in Combination with Oxygen or Carbonic Oxide, is 



Dextrorotatory. 



A. Oxy-Hcemoglobin. 



The diluted solution of Oxy-hsemoglobin, previously referred to, 

 was employed. This solution, containing 1*223 gramme of haemoglobin 

 in 100 c.c, was thoroughly saturated with oxygen before, being 

 subjected to polarimetric observation. 



* The part of Section 1 of this paper -which follows has been recast, and the 

 observations described under A and C added, since this paper was submitted to the 

 Royal Society. — March 5. 



t Zinoffsky, O., '"Ueber die Grrosse des Hoenioglobinrnoleculs," ' Zeitschrift f. 

 physiol. Chemie,' vol. 16 (1886), p. 23. 



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