AGRICULTURAL CHEMISTRY AGROTECHNY. 805 



the point of most rapid agglutiuation, viz, at a tiydrogen ion concentration of 

 about 3X1G — " normal, a figure whicli agrees witli ttiat obtained by Micliaelis 

 and Rona. 



" The solution or dispersion of euglobulin by electrolytes is shown to be much 

 influenced by the nature (especially as regards valency) of the constituent ions 

 and to be of two general types: (a) ' Electrical ' type of solution in which the 

 euglobulin dispersion is accompanied by the acquisition of an electric charge by 

 the protein particles, the sign of which is similar to that of the more potent 

 ion of the electrolyte employed; (b) 'molecular* type of solution, in which the 

 dissolved euglobulin is electrically neutral. 



" In type (a) the dispersion is considered to result from a specific adsorption 

 of the ion possessing the higher valency, in (b) from a molecular union with 

 (Hardy) or adsorption of (Schryver) the salt as a whole. Botli types of 

 solution are accompanied by loss of electrical conductivity in the liquid. 



" The electrical type of solution is well seen in case of disjiersion by such salts 

 as sodium citrate and lanthanum nitrate in low concentration; in case of the 

 more ordinary salts, containing mono- or divalent ions only, the electric forces 

 concerned are not powerful enough to disperse globulin until the concentration 

 is raised to a point where molecular solution talies place. In the case of sodium 

 citrate, the electrical type of solution was found to change to the molecular 

 type as the concentration of the salt was increased. 



" Euglobulin, when denatured by heat, no longer i>ossesses the property of 

 forming the molecular type of solution with electrolytes. On heating the latter, 

 in some cases the degree of dispersion is merely diminished, and the protein 

 particles acquire an electric charge, whose sign is determined by the more 

 potent ion of the electrolyte employed; in other cases agglutination takes place. 



" The reaction of acid and allialine solutions of euglobulin is greatly influenced 

 by the addition of electrolytes, the hydrogen and hydroxyl ion concentration 

 being reduced respectively. In case of the former the effect is much increased 

 with rising valency of the anion, and in alkaline .solution the result is deter- 

 mined by the valency of the cation. The influence of electrolytes in causing 

 pi'ecipitation of globulin dissolved in acid and alkali may. in some instances, be 

 adequately explained by the alteration in reaction ; in this way solutions too acid 

 or too alkaline for agglutination of the globulin may be adjusted to the Isoelec- 

 tric point by the addition of an appropriate electrolyte. 



" Precipitation by electrolytes may, however, also take place in solutions 

 whose reaction is still far removed from that of the iso-electric point. In these 

 instances it is attributed to neutralization of the electric charge originally car- 

 ried by the protein particles by means of a specific adsorption of the oppositely 

 charged ion of the electrolyte ; the effect is related to valency. 



" In the properties regarding solution and precipitation . . . euglobulin, in 

 common with caseinogen and the vegetable globulins, presents a very interest- 

 ing analogy with heat-denatured proteins. Euglobulin differs from heat-de- 

 natured protein in its capacity to form solutions with electrolytes in which the 

 protein particles are electrically neutral." 



The hydrolysis of organic phosphorus compounds by dilute acid and by 

 dilute alkali, R. H. A. Plimmer (Biochevi. Jour., 7 (1913), No. 1, pp. 72-80). — 

 In these experiments it was found that ethyl phosphoric acid, glycerophos- 

 phoric acid, and phytic acid are hydrolyzed by acid but are not affected by 

 alkali. Stability to alkali is consequently considered a property of phosphoric 

 acid esters. 



" It is not known how the phosphoric acid is combined in phosphoprotein, 

 but it is probably united with one of the amino acids. Hexosephosphoric acid 



