214 CHEMISTRY OF THE PROTEIDS CHAP. 



Walker's views on amphoteric electrolytes from the standpoint of 

 the electrolytic dissociation -theory have been summarised by John 

 Johnston 1 in the following way: If H'X'OH is an amphoteric 

 electrolyte with the acid-constant k a and the base-constant k 6 , and 

 if K w is the dissociation-constant of water : 



., 



K 



VK w + k a -[ 

 l+_- 



[OH - ] 



[H + ] 

 [HX + ] = ^-[H+]-[H-X-OH] 



"-w 



k.-[H-X-OH] 

 [H + ] 



II. GENERAL ACCOUNT or SALT-FORMATION 



In working with amino-acids and with albumins it is necessary to 

 constantly keep the salt-forming power of these substances before our 

 mind's-eye, in addition to their physical characteristics, which will be 

 explained later on. Glycocoll, being the simplest amino-acid, ia 

 therefore taken as a type. 



Normal Glycocoll, NH 2 .CH 2 .COOH. Winkelblech assumes that 

 a watery solution of glycocoll contains 9 9 '9 6 7 per cent of hydryated 

 but non-dissociated molecules, 



H H yO H X H H sO 



N - C - C >N - C - C. 



H H X)H HCT H H X OH. 



Normal glycocoll. Hydrated glycocoll. 



while the minimal remainder is made up of a few ions and of non 

 hydrated glycocoll molecules. He explains the neutral reaction of a 

 watery solution of glycocoll as being due to the want of dissociation 

 of the hydrated amino-acid. Although, then, the presence of glycocoll 

 leads to a union of the water-ions with the amino-acid, there is no 

 hydrolytic dissociation of the newly-formed compounds. A hydrated 

 amino-acid does not dissociate, because both the acid and basic radicals 

 are very feeble. 



Walker 2 believes that the glycocoll molecules in watery solutions 

 either form internal salts or that they unite in pairs, in such a way 



1 J. Johnston, Eer. d. deutsch. diem. Ges. 37. 3625 (1904). 



2 James Walker, Zeitschr. f. physik. Chem, 49. 82 (1904), and independently by 

 the author, Trans. Oxford Junior Scient. Soc. 1904. 



