208 [December, 



action of the membranes. To determine this point a series of careful experi- 

 ments were instituted with the following substances; albumen, fibrin, yolk of 

 hen's egg, warm blood, cold blood, putrescent blood, warm serum, cold serum, 

 putrescent serum, and urine. In no case did the presence of these substances 

 produce a crystalline deposit of the oxalate of lime. Each experiment was per- 

 formed in several different ways, and under different circumstances ; sometimes 

 the densities of the solutions of the chloride of calcium and oxalate of ammonia 

 were varied, at others the temperature and conditions of the foreign body. But 

 one result attended all these experiments no crystalline deposit. In many 

 instances we have mingled the interior and exterior fluids, in both of which 

 crystals had been produced by the action of the membrane, and in every case 

 the precipitate of the oxalate of lime thrown down consisted of irregular granules 

 without any crystalline form whatever. Does not this prove conclusively that 

 the simple presence of the different membranes did not cause the change of the 

 physical form of the precipitate? 



The next question which presented itself was, whether dry membranes exert a 

 physical influence upon substances passing in solution through them, capable of 

 changing their physical forms ? To determine this point we performed several 

 experiments with dry membranes, with solutions of the chloride of calcium and 

 oxalate of ammonia, varying the relative positions and densities of the fluids in 

 each experiment. In no instance was a regular crystalline deposit obtained. 

 In only one experiments, two or three octohedral crystal occurred in the midst 

 of millions of irregular particles. 



All our experiments, thus far, prove that dry membranes exert little or no 

 physical influence upon chemical substances in solution passing through them. 

 Our next subject was to ascertain the influence of inorganic septa, during the 

 endosmotic action. In our experiments we used thin vessels of baked clay. 

 These were filled with a solution of the chloride of calcium and immersed in a 

 glass jar containing a solution of the oxalate of ammonia. The relative posi- 

 tions and densities of these fluids were also changed. In no instance did we ob- 

 tain a regular crystalline deposit. So far then as our experiments go, we are 

 able to assert, that inorganic septa do not exert a physical influence upon chemi- 

 cal substances passing through them, capable of changing the arrangement of 

 their molecules. 



Experiments 7cpo?i the physical influence exerted upon chemical substances in solu- 

 tion, as they pass through the cell walls of vegetables. 



Immersed the cut end of a stalk of Indian corn in a solution of the chloride of 

 calcium, and allowed it to remain for 18 hours, at the end of which time it was 

 removed and placed in a solution of the oxalate of ammonia, in which it re- 

 mained for a similar length of time. When thin slices of the corn-stalk were 

 examined under a magnifying power of 210 diameters, a crystalline deposit of 

 the oxalate of lime, was found to have taken place within the hexagonal cells of 

 the vegetable, which presented the appearance represented in Figure IX. This 

 differs widely from the deposit formed when solutions of the oxalate of ammo- 

 nia and chloride of calcium are brought into immediate contact. The precipi- 

 tate thus formed consisted of irregular granules. 



The crystals deposited within the cells of the corn, differed widely also 

 from those formed when the intestines of a raccoon or a sheep were filled 

 with solutions of the oxalate of ammonia, and immersed in solutions of the chlo- 

 ride of calcium. 



Immersed sections of different lengths of the stem of a young and verdant 

 benne plant, in a solution of the acetate of lead, and then transferred them to a 

 strong solution of the proto-sulphate of iron. When thin sections were exam- 

 ined under the microscope, beautiful square and lozenge-shaped plates had crys- 

 tallized in all the hexagonal cells. 



When .the broad thick leaf of an endogenous plant was placed alternately in 

 solutions of the same chemical substances, a crystalline deposit took place 

 within its cells, which differed in form from that within the cells of the benne 

 plant. Different vegetables were immersed in different chemical solutions, 



