EFFECT OF BOG WATER ON SWELLING 



91 



The calcium nitrate solution is of the concentration in which 

 this salt enters into nutrient solutions. All measurements were 

 closed at the end of forty hours. Some swelling was still in 

 progress, but the rate of increase in the swamp water had ap- 

 proached the end point or zero. 



The equivalence of the effects of distilled water and of bog 

 water is obvious and the lessened swelling in swamp water is also 

 demonstrated, while the swelling is greater in calcium nitrate 

 solution than in the swamp water. 



Another series was carried out in which sections of Opuntia 

 were swelled at temperatures of 18 to 20°C. in acidified and salt 

 solutions. It is to be noted here that while rise in temperature 

 retards imbibition in simple gels, yet this law cannot apply 

 directly to the swelling of biocolloids or living plants. The 

 measurements of swelling of Opuntia in various solutions at the 

 given temperature was as below: 



The measurements in swamp water alone and with acid include 

 the full increase in ninety-six hours while the others extended 

 over from twenty to forty hours. 



No important effect can be ascribed to the acidification of 

 swamp water. The swelling of the sections in the hundredth- 

 molar solution of potassium nitrate was but little below that in 

 the swamp water but when this solution was similarly and 

 equally acidified, a decrease ensued. 



THE PLANT WORLD, VOL. 21, NO. 4 



