102 CHEMICAL STATICS 



had been united with the edestin. The character of the acid 

 united with the edestin varies with that of the salt employed for 

 solution of the edestin. When the salt is sodium chloride, the acid 

 is HCl, when it is ammonium sulphate, the acid is H2SO4. The 

 combination is apparently facilitated by a weakly acid reaction, 

 not necessarily induced by the same acid as that with which the 

 edestin combines. Osborne attributes this phenomenon to the 

 strength of edestin as a base; the compound which is formed, 

 however, must be practically undissociated so far as CI' ions are 

 concerned, otherwise, having regard to the extremely low equiv- 

 alent-concentration of protein in the solutions in which it is 

 formed, we should attribute to edestin a basic function of a magni- 

 tude wholly inconsistent with the fact that it is an amphoteric 

 acid. Therefore, it does not follow that these proteins are stronger 

 bases than they are acids because they can displace hydrochloric 

 acid from its combination with sodium hydrate, as Osborne 

 assumes, for this phenomenon may be interpreted by merely 

 supposing that the protein can combine with either constituent 

 of the organic salt, but that the compound with HCl produces 

 fewer CI' ions than the Na+ ions produced by the compound with 

 NaOH. A further discussion of this phenomenon will be found in 

 a later chapter. (Chap. VI, section 6.) 



The fact that the occurrence of decomposition of neutral mineral 

 salts through the agency of animal proteins has not been generally 

 recognized, is probably attributable to the fact that it has not been 

 carefully looked for, and that the proteins which are most readily 

 obtained in the pure condition are not usually prepared under 

 conditions favoring the formation of protein compounds through 

 the decomposition of inorganic salts. 



Two compounds of edestin with acid (hydrochloric) appear to 

 exist. The one, which Osborne terms the monohydrochloride, 

 contains an amount of acid-equivalent to 0.7 cc. N/10 HCl per 

 gram of the protein, and is insoluble in water; it is, however, 

 soluble in salt solution and is deposited therefrom in crystals on 

 dialysis. The other compound of edestin with hydrochloric acid 

 contains just sufficient acid to hold the protein in solution, and is 

 termed by Osborne the dihydrochloride. The quantity of HCl 

 required to just hold one gram of edestin in solution is 1.4 cc. 

 of iV/10 HCl. The acid-equivalent, for monobasic acids, at 

 "saturation" of the acid with edestin is therefore 14 X 10"^ 

 gram-equivalents per gram. The quantity of alkali which will 



