160 



MacDOUGAL and SPOEHR— components AND 



by glycocoll on agar. No final explanation for this behavior has as 

 yet been obtained. Of great interest, however, are the results ob- 

 tained with a number of glycocoll compounds. Swelling tests were 

 made in the usual manner with the following compounds : ( i ) Gly- 

 cocoll which is approximately neutral in reaction and amphoteric in 

 behavior. (2) Glycocoll ethyl ester; in this compound the acid 

 radicle has been neutralized, is distinctly alkaline and acts as a weak 



TABLE IV. 



base on the swelling of agar. However, in solutions of this sub- 

 stance agar does not attain the same swelling above that of water as 

 it does in the amphoteric glycocoll. On account of the relatively 

 rapid hydrolysis of glycocoll ester in water, fresh solutions were 

 frequently prepared for renewal in the swelling tests. (3) Glycocoll 

 ethyl ester hydrochloride in which both the basic and acid portions 

 of the glycocoll molecule have been neutralized. (4) Glycocoll hy- 

 drochloride which reacts as an acid in water solution and shows the 

 typical acid behavior in the swelling agar. The solutions were all 

 in o.oi molar concentration. The absolute increases in terms of 

 thickness and volume are as below : 



