93 



Method of crystallization. 



For the crystallization of the haemocyanin I have followed 

 both tlie methods of Hofmf.ister (Q) and Hofkins-Pinkus (10) for 

 egg-albuniin, but have fouiid no advantagc whatever in the lat- 

 ter, the haemocyanin having crystahized easily, and equally well, 

 with both nietliods. 



A saturated solution of amtnonium sulpliate was added 

 drop by drop to the blood, sliaking after each addition to re- 

 dissolvc the precipitate forined, unti! the solution, when agita- 

 ted, became again clear. If the solution becomes too turbid, wa- 

 ter is added, drop by drop, until the turbidity disappears. A so- 

 lution of acetic or sulphuric acid may be ndded until a muddy 

 appearance is obtained. The glass containing tiie solution was 

 covered with filter paper and left to stand. A more rapid or a 

 slower crystallization is obtained according to the quantity of 

 ammonium sulphate solution added i. e. according to the ammo- 

 nium sulphate concentration of the solution. If the ammonium 

 sulphate solution be added in an exactly sufficient quantity, 

 crystallization takes place rapidly. Thus the formation of crystals 

 may begin after the Ijpse of a few minutes, a quarter of an hour 

 or even several hours or days, according to the ammonium sulphate 

 concentration of the solution. Naturally the temperature of the 

 room and other physical factors have an influence on the rapidity 

 of the crystallization. By sliaking the solution crystallization is ha- 

 sténed. When large ciystals are desired, the solution should be left 

 to stand without sliaking. In this way tlic crystals, transparent and 

 of a greenish-blue colour, may attain an excepticmally large size. 



By shaking the solution before crystallization is ended, a se- 

 cond and very abundant crop of crystals may be obtained but 

 the crystals, in this case, are s'mall. 



Haemocyanin of Octopiis Vii/garis. 



FoUowing the method described above, the haemocyanin of 

 the blood of Octopus vulgaris may crystallize in three different 

 forms as follows : 



