34 



Scientific Proceedings (95). 



Three groups of substances were selected for these tests; (1) 

 succinic acid and its amido-compound, a amino-succinic or as- 

 partic, which are dibasic, and its amide, asparagin, which is 

 monobasic; (2) acetic acid and a amino-acetic acid or glycocoll, 

 which are monobasic; (3) propionic acid and a amino-propionic 

 acid or alanin, also monobasic. 



The swellings of sections of agar and a mixture of 8 parts agar 

 and 2 parts oat-protein are selected for discussion at the present 

 time. The measurements were made with the type of auxograph 

 which has been previously described. The principal end results 

 are given in the following table. 



Hydration of agar and agar-oat-protein in organic acids and their amido-compounds 

 at i6°-i7° C. Trios of sections .10-.23 mm. in thickness from plates cast from 

 2.5 per cent, solutions were used. Such plates were shrunken in thickness by 

 dehydration in 48-60 hours at i8°-22° C Duration of swelling 20-60 hours. 

 Expansion in percentages of dried thickness. 



Concentra- 

 tion. 



Water Dis. 



Succinic 

 Acid Mol. 



Aspartic 

 Acid Mol. 



Asparagin 

 Mol. 



Acetic 

 Acid 

 Normal. 



Glyco- 

 coll 

 Mol. 



Propionic 



Acid 

 Normal. 



Alanin 

 Mol. 



Agar. 



0.05 



O.OI 

 0.002 



0.0004 

 0.00008 



2413% 

 2739 



IO91 



1273 

 1600 

 1750 

 2528 



827 

 1270 

 1400 

 1788 

 2080 



2308 

 2365 

 2440 

 2720 

 3250 



1433 

 1560 

 1790 

 1955 

 2640 



2965 

 3166 

 2605 



1200 

 1300 

 1625 

 1800 



1474 

 2421 

 2790 



Agar 8, Oat-Protein 2 Parts 





2100% 



















263O 

















0.05 





700 



855 



1867 



1090 



1938 



800 



2046 



O.OI 





864 



900 



2455 



1255 



2340 



1000 



2317 



0.002 





909 



1670 



2523 



1738 



3050 



1250 



2410 



0.0004 





II36 



2600 



2675 



2238 



3000 



1591 



2273 



0.00008 





2330 



3050 



2600 



2480 





1864 





The deductions to be drawn from these figures, all being aver- 

 ages of 3 to 9 measurements, are numerous, but attention must be 

 confined to a few pertinent cases. 



1. It is to be seen that equimolecular concentrations of the 

 three organic acids present small divergence of effect on agar and 

 more positive differences in agar-protein. 



2. Agar swells more in succinic acid than in its amido-com- 



