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Prof. A. Gamgee and Mr. A. Croft Hill. [Jan. 31, 



tially as follows : to a solution of crystallised haemoglobin, either pre- 

 pared by Hoppe-Seyler's method or by the ammonium sulphate method y 

 dilute hydrochloric acid is added in extremely small quantities, until 

 a flocculent brown precipitate falls which is immediately dissolved by 

 the slightest excess of acid. The solution then no longer exhibits the 

 beautiful red colour of -haemoglobin, but has assumed a brown colour. 

 Not only, remarks Schulz, has its colour changed, but a complete 

 separation has occurred between the albuminous and coloured con- 

 stituents of haemoglobin. If to the solution, which has now a faint 

 acid reaction, about one-fifth of its volume of 80 per cent, alcohol be 

 added and the mixture be shaken with ether, the whole [sic] of the 

 colouring matter is taken up by the ether, whilst the subjacent 

 aqueous-alcoholic, perfectly clear solution contains the decolourised 

 albuminous matters. Schulz gives particular directions as to the 

 precautions which must be taken in order that the separation of the 

 ethereal solution of the colouring matter should be complete, stating 

 that a certain relation must exist between the proportions of water, 

 alcohol, and ether, which must be experimentally determined in each 

 case. By the above process there is obtained a more or less brownish- 

 yellow solution, containing both alcohol and water and having a 

 faintly acid reaction. On neutralising this solution with ammonia, a 

 faintly yellow, coarsely flocculent precipitate falls. The latter is 

 rapidly separated by filtration and then washed with water. When 

 the excess of ammonia has been removed, the precipitate commences 

 to dissolve in the wash water. At this stage, the precipitate is dis- 

 solved in water with the aid of a few drops of dilute acetic acid. 

 Solution occurs rapidly and completely. The excess of acid is now 

 removed by dialysis continued for some days, the dialyser being sur- 

 rounded by distilled water. There is thus obtained a clear, odourless 

 and tasteless solution of globin the reaction of which is perfectly 

 neutral. 



It is not our object to examine in this place the reactions presented 

 by solutions of globin, and which have led Schulz to place it among 

 the " Histons." 



Before describing briefly the methods we employed to prepare the 

 solutions of globin which we investigated optically, we desire to make 

 certain observations on certain points in Schulz's statement. In dis- 

 cussing the quantity of dilute hydrochloric acid needed to effect the 

 decomposition of haemoglobin, he merely remarks that it is extra- 

 ordinarily small ("Die zu der Spaltung erforclerliche Menge von 

 Saure ist ausserordentlich gering, &c"). We have determined the 

 quantity of decinormal hydrochloric acid required to effect the decom- 

 position of a solution of CO-haemoglobin of known composition. As 

 a result of very careful experiments with a solution containing^ 

 1-84 grammes dissolved in 200 c.c. of water, there were required 



