.36 



strings were attached. Moreover, filaments of Spirogyra wliicli liad been 

 exposed for only ten minntes to the action of this oxalate solution and 

 had still preserved their full turgor, were incapable of repairing the 

 injury done after returning them to well water rich in lime, and they 

 died after twenty-four hours. Even five minutes' action ultimately 

 caused death. In a weaker solution (0.5 i)er cent) of oxalate the nucleus 

 does not shrink to a thread, but slowly swells up and finally becomes 

 an irregular, scalloped figure. In a still higher dilution (0.1 per cent) 

 the poisonous action proceeds so slowly that it requires a number of 

 days to comi^letely kill all the cells. 



In other species of alg^^, such as Vaucheria, Mougeotia, Zygnema, 

 Cosmarium, (Edogoniiim, Chladophora, Splicvroplea^ etc , death, accom- 

 })anied by swelling of the chlorophyll bodies, occurred after twenty-four 

 hours' action of a solution of 0.5 })er cent. Diatoms died in this solu- 

 tion in fifteen hours, but in a solution of 0.03 per cent some diatoms 

 were still alive after three days. In higher dilutions the poisonous 

 properties decrease rapidly.^ Phanerogams also are easily attacked 

 by oxalates. When placed in a 2 per cent solution of neutral potassium 

 oxalate, the nucleus of an onion shows a contraction of about one-fifth 

 of its normal diameter within ten to fifteen minutes. Leaves of EJo-dea 

 canadensis and YalUsneria spiralis were killed completely in thirty-six 

 houTwS 2 in a 1 per cent solution. The control experiments with potas* 

 sium tartrate or sulphate, failed in all cases to show similar action. 

 The claim, therefore, that lime salts are necessary to precipitate tar 

 taric acid in plants that contain tartrates instead of oxalates has no sup- 

 port, since neutral tartrates are not poisonous, as are neutral oxalates. 



The cj^toplasm succumbs last, and its death is probably' a secondary 

 effect, due to the death of the nucleus and the chlorophyll body. 

 Indeed it can be easily seen that the cytoplasm dies sooner when the 

 number of chlorophyll bodies contained in it is increased. It is on this 

 account that the circulation of the cytoplasm lasts much longer in the 

 root hairs of Chara when under the influence of a dilute solution (0.5 per 

 cent) of potassium oxalate than it does in the cells of the internodes filled 

 with chlorophyll bodies. An equally dilnte solution of neutral potassium 

 tartrate shows no injurious action in the same length of time. The 

 writer's explanation of the poisonous action is as follows: Judging from 

 the most characteristic properties of soluble oxalates, that of i^recip 

 itating lime from even highly diluted solutions of lime salts and that 

 of depriving lime compounds generally of their lime and of converting 

 it into the insoluble oxalate, he inferred from the peculiar poisonous 

 action the existence of calcium protein compounds in 

 the organized particles from which the nucleus and 



^This, however, is not the case with free oxalic acid (p. 38). 



-There are some remarkable cases iu which monopotassium oxalate exists in the 

 cell sap and still produces no injury, as, for instance, iu Ihimex and Oxalis. In these 

 cases it is uecessary to iissu:r.e ;ni unusual density of the tonoplasts— that is, a density 

 sufticient to protect the nucleus and protoplasm. 



