FUNCTIONS OF LIME SALTS. 45 



shows plainly that it is impossible to accept the view that potassium 

 oxalate becomes dissociated in the cells and that it is the free oxalic 

 acid which, on account of its acidity, kills the nucleus, since potassium 

 nitrate would be expected to act in just the same way." 



It will of course be difficult to prove microchemically the formation 

 of calcium oxalate in the chlorophyll body or nucleus when potassium 

 oxalate is left to act upon them, since the amount of calcium in them 

 is naturally very small, judging- from the great molecular weight of 

 the organized proteids with which it would be combined. Moreover, 

 the formation of distinct crystals of calcium oxalate would be impeded 

 by the peculiar consistency of the living structures. It was claimed 

 that in view of the highly complicated conditions in the cells the 

 assumption of a direct connection between a working cause and an 

 observed pathological result could not be admitted, as the latter might 

 be simply the effect of primarily produced "disturbances of nutri- 

 tion." However, this claim can not be sustained in the case of the 

 action of neutral oxalates upon the nuclei, for in the first place this 

 proceeds very rapidly in concentrations of over 1 per cent, and in the 

 second place the processes of metabolism in objects like Spirogyra 

 proceed very slowly. 



Further observations by Migula 6 deserve to be mentioned here, as 

 they demonstrate that free oxalic acid is among the most poisonous of 

 organic acids. For example, in a solution of 0.004 per cent of free 

 oxalic acid the nucleus of Spirogyra orbicularis was observed to swell 

 up, frequently to six times its normal volume, and become turbid and 

 opaque, while the cytoplasm still remained alive for some time. In 

 stronger solutions the cells die too quickly to show such character- 

 istic symptoms, their death in this case being due chiefly to mere 

 acidity. 



When some filaments of Spirogyra majusculaweve placed in 500 cc. of 

 a solution of free oxalic acid c in even as high dilution as 0.0001 per cent, 

 the writer observed great injury to some of the threads after five days. 

 In most of the cells the plasma strings were retracted, the nucleus was 

 contracted and rolled to the cell wall, and the sinuate margins of the 

 chlorophjdl bands were swollen up and numerous little drops became 



« When acting on Spirogyra the potassium oxalate seems to pass direct to the 

 nucleus through the plasma strings and not through the tonoplast, but, on the other 

 hand, when potassium oxalate is contained in the cell sap of certain plants it seems 

 to be confined there by the density of the tonoplast, which also prevents its direct 

 contact with the nucleus in this case. In this connection Migula observed some 

 interesting facts with Spirogyra kept in well water to which very small quantities 

 of organic acids had been added. These were gradually oxidized in the cells into 

 oxalic acid of which some was retained as neutral oxalate in the cell sap, and yielded 

 a precipitate of calcium oxalate when placed in a diluted solution of lime salts. 



& The Influence of Dilute Acids on Algae, Breslau^ 1888. 



c Purest water distilled from glass vessels was used for all experiments with 

 Spirogyra. 



