Effect of Certain Organic Acids and Amino Compounds. 

 TABLE 47. 16 to 18 C. 



59 



The proportion of the acid and the asparagine being too high 

 to be of any physiological interest, new plates with half the 

 quantity of acid and amine were prepared, and these came down 

 to a thickness of 0.32 and 0.33 mm., which swelled 1,875 per cent 

 in distilled water as compared with agar, which showed a hydration 

 capacity of 2,700 per cent. The effect in this trial was not so 

 marked as in the first series, but it is evident that the incorpora- 

 tion of the asparagine in any proportion in the colloid affects 

 hydration to a greater extent than the perfusion of the asparagin 

 in the same concentration, which in this case gave swellings of 2,300 

 per cent. Even a 0.1 M solution with double the amount present in 

 the solution did not reduce the hydration to the limits shown by the 

 agar-asparagine plate used in this test. The asparagine was present in 

 such amount that if diffused out of the sections it would have made a 

 0.04 M solution in the 30 c.c. of water in the dish. 



Asparagine was now applied in a series of concentrations to sections 

 of agar of the above swelling capacity in water and it was found that 

 hydration was actually increased or accelerated by the presence of the 

 amine. That this result did not simply appear by faulty comparisons 

 was shown by the following replacement test: 



A trio of sections which had been swelled in distilled water to a total 

 of 2,630 per cent, and which had stood in the solution without any 

 perceptible change for a few hours after the close of the test, was now 

 treated with a 0.01 M asparagine solution. The mechanical disturbance 

 which might result from changing the liquid in the dishes was mini- 

 mized by fractionization. About one-third of the water was removed, 

 the level was raised by the addition of asparagine solution, and this 

 was repeated about a half-dozen tunes, the final result being a solution 

 which was diluted slightly below the hundredth normal. A slow 

 expansion began at once, which continued for about 20 hours, which 

 raised the total hydration of these sections to 2,890 per cent, an in- 

 crease of 230 per cent, due to the action of the asparagine on sections 

 which had undoubtedly been reduced in mass somewhat by solution 

 from the surfaces. 



When asparagine is applied to mixtures in which the gelatine is 

 replaced by an albumin, the results included some special reactions. 

 Plates of agar and oat-protein were made up to contain 8 parts of the 



