Fundamental Features of Phytocolloids. 



21 



with their long axes parallel to the surface, as shown in figure 7, which 

 was furnished by Miss Carey in response to the request of the author. 



The extraction and preparation of a number of substances, includ- 

 ing protein from oats, albumin and globulin from beans, the total pro- 

 tein of beans, asparagin, aspartic acid, etc., was undertaken by Dr. 



FIG. 7. Longitudinal section of an agar plate dried at 70 C. without superficial shrinkage, with 

 development of elongated spaces or cavities which are found when the film is hydrated 

 Drawn with camera lucida by Miss C. L. Carey. X78.5 diam. 



FIG. 8. Scale designed for measuring thickness of paper and suitable for 

 determiningjjthickness of sections of plates of biocolloids. Sheets of a 

 thickness of 0.001 to 0.11 inch(= 2.8 mm.) may be measured (see fig. 23 

 for calipers used in measuring larger objects). 



Isaac Harris, of|Squibb & Sons' laboratories, New Brunswick, New 

 Jersey, while Mr. E. R. Long furnished preparations of such sub- 

 stances as zein, which made it possible to make up plates of biocolloids 

 entirely from products of plants. 



The swelling of mixtures of agar and of the protein extract of bean 

 in plates 0.3 to 0.4 mm. in thickness were as shown in table 3. 



