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BASCOMBE BRITT HIGGINS 
underlying cells dry out rapidly. As the wilting spreads the amygdalin 
comes in some way in contact with the emulsin and is broken down. 
Each molecule of amygdalin breaks down into four molecules (one 
each of hydrocyanic acid and benzaldehyde and two of glucose), 
thus materially increasing the osmotic pressure in the cells where this 
occurs. The increased osmotic pressure enables them to draw water 
from the adjoining cells and swell until this pressure is more nearly 
equalized. 
Since HCN has been found to increase the activity of proteolytic 
enzymes, it is quite probable that its presence in the enlarging cells 
causes the digestion of the plastids. Butkewitsch (7) found that 
addition of HCN accelerated the self digestion of the proteins in 
crushed seeds of several plants. Vines (29) also noted this property 
of HCN and suggested that its function in seeds might be to facilitate 
proteolysis of the reserve materials on germination. 
Amygdalin Removed from Area of Leaf Occupied by the Mycelium. 
— One question which naturally arises is, Why is this separation layer 
always formed at such a distance from the acervulus as to include the 
fungus mycelium? This question is readily answered according to the 
previously discussed theory, if the fungus is capable of using amygdalin 
as a food; since in that case the amygdalin from the cells in the im- 
mediate neighborhood of the mycelium would be absorbed by it. 
The separation layer would then be formed by the cells outside this 
region, the amygdalin of these cells breaking down and producing the 
necessary osmotic pressure. The fungus could certainly use a part 
of the amygdalin molecule (e. g., the sugar), if it contains an enzyme 
to split the amygdalin into these simpler compounds. 
To test this hypothesis, several cultures of the fungus from P. 
virginiana, P. mahaleb, P. pennsylvanica, and P. avium all growing on 
sterilized bean pods were used. From four cultures the liquid in 
the bottom of the tube was filtered off and a quantity of absolute 
alcohol added to the filtrate. A flocculent precipitate was soon 
formed. The liquid was again filtered, the precipitate washed with 
a mixture of ether and alcohol, dried and redissolved in 8 c.c. of water. 
The liquid from each tube was thus treated separately. As checks, 
the extract from two of the cultures was boiled and to each of the 
four, 2 cc. of a 5 per cent solution of amygdalin was added. A few 
drops of chloroform were added to each as an antiseptic. The prepara- 
tions were then corked and set in a locker in the laboratory. After 
