210 SOAPS AND PROTEINS 



words, a system representing a " solution " of water in the basic 

 globulinate. For this purpose 2 grams of the moist globulin 

 were carefully weighed into each of a number of test tubes and to 

 each was then added 0.5 cc. of an alkali of proper strength to 

 yield the final concentration in the whole of each of the systems 

 indicated in Table LXV. The descriptions refer to the appear- 

 ances of the mixtures at the end of twenty-four hours, twenty 

 of which were spent in an ice box and four at room temperature. 

 The photographic appearance of the three sets of tubes (all 

 made at the same time, from the same globulin and under iden- 

 tical circumstances) is shown in the Figs. 98, 99 and 100. It is 

 apparent that these potassium, sodium and barium globulinates 

 (like the corresponding soaps) have greater solvent powers for 

 water (and hence gel in the presence of a larger volume of the same) 

 than has the original " neutral " globulin (or the original fatty 

 acid). But of the three soap-like compounds the potassium 

 globulinate is most soluble in water, wherefore it is the first to 

 go through a jellying stage " into solution." Sodium globulin- 

 ate occupies a middle position in this regard. Barium globulinate, 

 while possessed of relatively low powers of hydration is so insolu- 

 ble in water that it maintains its gel state throughout the series 

 of experiments. 



Having seen that with progressive additions of alkali, neutral 

 globulin in the presence of a fixed volume of water passes suc- 

 cessively from (1) a (relatively) non-hydrated material through 

 (2) a state in which water is dissolved in it, into (3) a state in 

 which it is dissolved in the water, we wished to see what were the 

 effects of mere dilution upon the final system and if the basic 

 globulinate thus formed could be precipitated a second time 

 (salted-out) by further addition of the alkali (as can a soap). Fig. 

 101 and Table LXVI answer these questions. The first five tubes 

 merely show again how with progressive increase in amount of 

 alkali (sodium hydroxid), " solution " of a " globulin " (really 

 solution of sodium globulinate) may be obtained. To such a tube 

 as 4 much water 1 may now be added without change, as evidenced 



1 Not, however, an unlimited amount, for in too much water hydrolysis 

 of the sodium globulinate takes place and the free acid (globulin) again begins 

 to fall out. This constitutes the principle upon which "globulins" are 

 obtained through dilution with much water. It is not the sodium globulinate 

 which falls out, or, in the terms of soap chemistry, it is not "the soap" which 

 is "insoluble" in water but the "fatty acid" resulting from hydrolysis. 



