growth of the resulting formation. Uo you note any movements? 

 What are they due to? Draw. 



114. Sea-vueed-like formations tliroiu/h t/ro^'tli of precipitation 

 membranes. Place a lump of fused CaCL, in the bottom of a tall jar 

 filled with concentrated Xa L ,CO, solution. Set aside for several days 

 and watch the development of a plant-like growth. 



115. Membranes formed throiii/Ji surface action, a. Shake a 

 few drops of olive oil in a test-tube with the following fluids ( a ) 

 water, and aqueous solutions of (b) XaCl (0.65^ ), (c) peptone, 

 (cl) soap, (e) haemoglobin, (f) albumin (g) sugar, (h) starch (i) 

 lecithin, and ( j ) gelatin ( 2 ( '/ ( ). In which does a permanent emulsion 

 occur ? \Yhy ? 



1). Perform the above experiment using chloroform instead of 

 olive oil. Results ? 



1 16. Formation of artificial cells surrounded by a film of modified 

 protein. Shake chloroform with an albumin solution. Can the 

 film be removed b}- repeated washing in water? Pour some of the 

 chloroform globules into a watch-glass of water and examine 

 under the microscope. Can you see the film? Does the chloroform 

 slowly evaporate ? 



If lecithin is dissolved in the chloroform, it will absorb water as 

 the chloroform evaporates, and a watery solution of lecithin can be 

 obtained surrounded by a protein film. Such a cell resembles in 

 many of its properties a sea urchin egg. Prepare some of these cells 

 by shaking a lew drops of a chloroform solution of lecithin 

 (m/8o) with albumin solution, washing with water and pouring 

 the globules into a watch-glass of water. X>cte from time to time 

 during the course of the hour their appearance under the microscope 

 and draw the stages observed. "When chloroform has been com- 

 pletely replaced by water add a drop of neutral red to the water in 

 the watch-glass. Is it accumulated by the cells? Try pricking the 

 cell with a fine needle to determine the consistency of the contents 

 and also of the membrane. 



C. FORCE OF DIFFUSION OSMOTIC PRESSURE. 



The energy of diffusion, or the tendency which two substances 

 have to mix, may be measured by separating them by a membrane 

 through which one of them can pass while the other can not. The 

 latter then produces pressure on the membrane and this pressure can 

 be measured. This is partly accomplished by the following 

 experiment. 



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