26o 



Scientific Proceedings (121). 



We therefore prepared another series of 10 per cent, and 40 per 

 cent, gelatin gels (10 grams air-dry gelatin in 90 grams water and 

 40 grams gelatin in 60 grams water) and poured the 10 per cent, 

 gel 4 times as deep in the petri dish as was the 40 per cent. gel. 

 These on drying should give gelatin plates of equal area and thick- 

 ness. After drying these plates they were allowed to imbibe 

 water as in the above experiment. Figure 2 shows the imbibition 

 curves obtained. Here again there is a marked effect due to the 

 initial concentration of the gel. Similar discs were placed in 

 iV/25 lactic acid (P H 2.49). It is well known that acid solutions 

 greatly influence rate of imbibition and amount of swelling of 



12 S4 36 46 60 7g 



HOURS 



Fig. 3. Showing imbibition curves (in N/25 lactic acid) for dried sections of a 

 10 per cent, gel and a 40 per cent. gel. Dried sections of equal surface area and 

 equal thickness. 



