414 Mr. W. B. Hardy. [Apr. 9, 



The globulin used throughout this research is that which is precipitated 

 from ox serum by dilution and slight acidification. 



Solution by Acids or Alkalies. Electro-positive or electro-negative globulin. 

 When acid or alkali is gradually added to a suspension of globulin in water, 

 the opaque suspension gradually changes to a clear transparent fluid. 

 Between the opaque suspension, from which the globulin settles on standing, 

 to the stage of limpid transparency there is no break. The most minute 

 addition of acid or alkali (in the absence of salts) converts the suspension 

 into a non-settling " solution " of low grade, which is opaque white from the 

 large size of the particles of globulin dispersed throughout it. Further 

 addition of acid or alkali raises the grade of solution. The globulin particles 

 become smaller and smaller until complete transparency is reached. 



The process can be reversed by dialysis, save that, at the lowest grade 

 attainable, no precipitate settles in the absence of disturbing factors. 



With the first addition of acid or alkali, and at the last stage of dialysis, 

 the globulin is electrically active, so that it moves in an electric field, the 

 direction of movement being that which one would expect if it combined 

 with the acid or the alkali to form a salt, and the specific velocity is quite, 

 or nearly, at its maximum value. A rise in the grade of solution is, on the 

 whole, associated with a fall in the specific velocity, never in my experience 

 with a rise in this value. The electric charge on the surface of the globulin 

 particles therefore appears to reach maximal density when the solutions are 

 still of exceedingly low grade. 



These facts can best be explained by assuming that true salt formation 

 occurs. This agrees with the view of all previous workers on the 

 interaction of proteids with acids or alkalies (Sjoqvist, Bugarsky and 

 Liebermann, and Cohnheim). Since globulins combine either with acids or 

 bases, they have both an acid and a basic function — they are amphoteric 

 electrolytes. 



The globulin salts ionise in solution ; therefore, in an electric field the 

 entire mass of proteid moves. They also hydrolyse, but the hydrolysis, 

 offers special features resembling those which Jordis has pointed out in the 

 case of sodium silicate, and Chevreul in the case of soaps. In both of these 

 cases hyper-acid salts are formed, while hyper-acid salts are formed on 

 dialysis of a solution of globulin by alkali, and hyper-basic salts on dialysis 

 of a solution of globulin by acid. 



By dialysis the degree of hyper-acidity or hyper-basicity can be raised,, 

 but, as Jordis finds in the case of silica, with continuously increasing 

 difficulty. With the rise in the degree of hyper-acidity or hyper-basicity, 

 the " grade " of solution diminishes, but, in the case of globulins, precipitation 



