266 S. TAKABAYASIII ; ON THE POISONOUS ACTION OF 



able objects within a few days and, although more slowly, even in 

 a dilution of 0.05^/^' That it is not merely the alkaline reaction 

 of such solution to which the noxious action must be ascribed, 

 becomes evident when we compare the effect of 0.0$% solutions 

 of sodium and ammonium carbonate. 



Further experiments have convinced me that it is impossible 

 to counteract the noxious action of 0.5^^ solution of ammonium 

 carbonate by administering at the same time cane sugar or 

 glycerol in i — 2^^ solution, but on applying ammonium carbonate 

 in a dilution of 0.05^^ I observed, in several cases at least, a 

 retardation of the noxious action, but not a complete prevention. 

 This result is evidently to be explained by the fact that the 

 ammonium carbonate enters much more quickly by osmosis into 

 the cells than the sugar or glycerol does. When the vegetable 

 cells are provided with a sufficient quantity of glycerol or sugar 

 before the ammonium carbonate enters, then the poisonous action 

 of the latter may probably be better counter-balanced. 



The phenoniena of the poisonous actions of ammonium carbon- 

 ate were principally the following : — the rootlets of the shoots were 

 softened by loss of turgor, became more translucent, and assumed in 

 many cases a brownish colouration ; isolated leaves placed in the 

 solution gradually exhibited brown spots and lost their turgor, 

 while the liquid assumed a yellowish colour due to organic matter 

 no longer retained by the cells whicli had died off. 



The objects which I used for these experiment were branches 

 of Polygomim fagopyrum, Polygoiiiiin tinctoj-iinn, Capsicum 

 longuvi, Ginko hiloba, and Qiicrciis, shoots of so)-a-beans, 

 peas, beans, and potatoes, petals of sun-flowers and of roses, 

 leaves of the mulberry tree and of the potato plant, and finally 

 algae, as Spirogyra. 



These observations induced me to modify my further experi- 

 ments in the following manner : — A part of the objects (A) was 

 left in darkness for several days until most of the reserve material 

 had been consumed by respiration ; the other part (B) was ex- 

 posed to the direct sunlight and kept at the same time in a 

 solution of \% cane sugar. Then the proper experiments com- 

 menced by placing several plants of each portion in solutions 

 containing 0.\% and 0.5% of the following salts, and kept in 

 darkness : — 



(I) Ammonium sulphate has a much weaker action than the carbonate. 



