314 



Transactions of thk Canadian Institite. 



\VOL. VII. 



In all cases the protoplasmic membrane was dissolved, or had not 

 been separated from the cell wall ; the strands had disappeared. 



The object of this experiment was to discover, if possible, the action 

 of poisonous solutions upon Spirogyra. In the case of CUSO4, HgCLj 

 and PbAj there was a peculiar formation of small dense particles in 

 the protoplasmic substance, showing that some chemical change had 

 taken place, resulting in a precipitate ; or in an action upon globules, 

 colourless by nature, within the protoplasm. These substances either 

 dissolved the protoplasmic membrane, or passed through it without 

 any apparent obstruction, as no plasmolysis occurred. These dark 

 particles were especially large and dark with the HgCl.. solution, a 

 result which in the case of a mass of cells would produce a darkening 

 of the general colour. Such a change took place in the case of leaves 

 which were acted upon by this solution applied to the cut ends of the 

 petioles. The darkening in the case of the FeSOi solution was entirely 

 different, being due to the action of the iron solution upon the walls 

 of the cells, producing a blue colour which appears black in mass. 

 This was shown particularly where the cells of the filaments were 

 joined. This dark colour was shown in the leaves whose petioles had 

 been dipped in a solution of FeS04, the veins becoming dark even to 

 their minute extremities. (See photographs i, 2, 3). The HCl 

 penetrated the cell wall quickly and dissolved the protoplasm. NaOH 

 and NH4OH quickly penetrated the cell walls, dissolved the protoplasm 

 and broke down the chlorophyll band. 



Poisonous solutions applied to the upper si'de of a leaf compared with 

 the same solutions applied to the lozver side. 



Seriks IV. 



Detached leaf of Primula stellata ; petiole in water ; time twenty- 

 four hours ; solution strength m/640. 



