190.°).] Oil the Optical Activity of Hmmoglobin and Globin. dSo 



20 c.c. of decinormal hydrochloric acid to effect the complete separa- 

 tion of globin from the colouring matter. 



We found that agitation with ether, unless repeated several times, 

 fails to remove all the colouring matter which is capable of removal 

 in this way. Further, we found that even when, as a result of agita- 

 tion with ether, the aqueous-alcoholic solution of globin is of the 

 faintest straw colour, on being neutralised with ammonia the preci- 

 pitated globin, which is at first colourless, assumes a somewhat reddish 

 tinge, and when subsequently dissolved in water faintly acidulated 

 with acetic acid the solution is much more deeply coloured than the 

 original aqueous-alcoholic solution. 



The following is the precise method which we followed in preparing 

 the solutions employed in our polarimetric determinations : — 



100 c.c. of a solution of four times crystallised haemoglobin, con- 

 taining 1*84 grammes of the substance, was diluted with 100 c.c. of 

 distilled water and treated with 20 c.c. of decinormal hydrochloric 

 acid. 44 c.c. of absolute alcohol were then added to the liquid, which 

 was placed in a stoppered separating funnel and thoroughly agitated 

 with its own volume of ether. The aqueous-alcoholic liquid having 

 been separated from the supernatant ethereal solution of colouring 

 matter was twice more agitated with fresh quantities of ether. By 

 proceeding as we have described, the separation of the solution of 

 globin occurred completely after the first agitation with ether, and the 

 solution after the third agitation only possessed a faint straw coloura- 

 tion. In certain cases, the globin was separated according to the 

 method of Schulz by precipitation with ammonia, the flocculent pre- 

 cipitate being subsequently dissolved in very weak acetic acid. In 

 this manner was prepared the solution of globin which served for the 

 first set of determinations recorded below. As it was impossible to 

 obtain in this way solutions sufficiently colourless to allow of their 

 rotation to be determined satisfactorily for light of the wave-length 

 of D, this was done as in the case of haemoglobin for light of the mean 

 wave-length of C. In the second set of observations, the rotation of 

 the aqueous-alcoholic solution resulting from the decomposition of 

 haemoglobin, after thorough agitation with ether, was determined. 



Globin a Lcevorotatory Substance. 



Preliminary observations having shown that solutions of globin 

 are optically active and Isevogyrous, the following sets of observations 

 were made with the object of determining the specific rotation of 

 solutions of the substance. 



1. A solution of globin in distilled water, but containing a little 

 acetic acid, was examined with the arrangement for red light, as was 

 used in the case of haemoglobin. The solution contained 2*4 grammes 



