64 KELLERMAN: EFFECTS OF CHEMICAL AGENTS 
strength of mercuric chloride to which various dilutions of other 
chlorides were added. The crossed line represents the action of 
the various dilutions of the chlorides alone. 
At the strong concentrations of the calcium, the check solu- 
tions containing only calcium were only slightly more rich in sugar 
than the solutions containing the mercury also. From x/10 to 
n/1,000, however, while calcium alone gave a slight increase above 
the normal starch transformation, the solutions containing mercury 
also were rapidly checked, until at 2/1,000 dilution of calcium the 
n/5,420 mercuric chloride completely checked starch transforma- 
tion. 
A similar series of experiments was made with barium chloride 
substituted for calcium, and with as marked results. Then a series 
was carried through using sodium chloride, with four concentra- 
tions of mercuric chloride. Here the amount of sodium chloride 
was so constantly in excess that the sodium and sodium-mercury 
lines run fairly near together on the chart. It seems, however, to 
indicate an increase of injurious effect at the last dilution. 
In conclusion I beg leave to acknowledge my indebtedness to 
Dr. B. M. Duggar, assistant professor of plant physiology, and 
Professor George F. Atkinson, professor of botany in Cornell 
University, for constant encouragement and every courtesy and 
assistance in the prosecution of this work. 
