310 CHEMISTRY OF THE PROTEIDS CHAP. 



EXPERIMENT 8 B 



In Experiment 8 A the only constant was the egg-white, namely, 

 1 ccm., while both the sublimate and the salt solutions were variables. 

 Following the suggestion of G. J. Burch the author repeated the 

 experiment with two constants, namely, the sublimate and the egg- 

 white, and two variables, the salt and the water, with Experiment 8 B, 

 while in Experiment 8 C the albumin and the salt were constants, the 

 sublimate and water being the variables. (The differences in the 

 electrolytic dissociation of NaCl and the hydrolytic dissociation of 

 HgCl were not taken into consideration.) 



The molecular weight of sodium chloride is 58*4, and a 'normal' 

 solution is made by dissolving 58 '4 grms. of this salt in 1000 ccm. 

 of water, sodium being monovalent. The molecular weight of mercuric 

 chloride (sublimate) is 270*6, and, as mercury is divalent, to obtain 

 a normal solution of sublimate equivalent to that of a monovalent 

 substance such as sodium chloride, one-half the molecular weight in 

 grams, namely, 135*3 grams, would have to be dissolved in 1000 ccm. 

 of water. The solutions used in this experiment were a two-fifth 

 normal sublimate solution, i.e. 54*1 grams in 1000 ccm. of water, and 

 a double-normal salt-solution, i.e. 116*8 grams in 1000 ccm. of water. 

 The reason for choosing a two-fifth sublimate solution was because 

 the insolubility of sublimate prevents a 'normal' watery solution 

 being made, its solubility being only 70 instead of 135 '3 grams in 

 1000 ccm. of water. The sodium chloride was used in double its 

 normal strength to bring the action of this salt quickly into play. 



Care was taken that the total amount of fluid amounted in each 

 case to 10 ccm., and that the sublimate, salt, and water were well 

 mixed before adding the albumin. 



25 ccm. of sublimate solution contain 1*3525 grams of HgCl 2 , 

 while 5 ccm. of salt solution contain 0-584 gram of NaCl. (Table on 

 p. 311.) 



The immediate results were : A showed no change, while in B a 

 dense flocculent coagulum appeared which commenced to settle after 

 10 minutes. The coagulum was so dense that ordinary letterpress 

 could not be seen through the test-tube. C contained finer flocculi 

 than B ; letterpress at first was just visible, but the writing became 

 more distinct after 10 minutes because of the settlement of the 

 flocculi. D resembled (7, but the flocculi were still finer, and hence 

 the print plainer than in C ; after 1 minutes individual letters could 

 be recognised, the sediment was finer and less abundant than in C. 



E to L exhibit a gradually descending series of opalescence. The 



