August, ’24] nickels: calcium arsenate dust for boll weevil 
477 
3. Accepting these qualifications we find that the digestive fluids of 
the oesophagus apparently do not render the arsenate of lead more 
soluble. (Further investigation should be carried on here). Secondly 
the digestive fluids of the honey stomach and stomach makes the powder 
1.28 times as soluble as it would be in water alone. Thirdly the intes¬ 
tinal fluids increase the solubility 3.75 times what it would be in pure 
water. 
Acknowledgments 
In carrying out this work the writer received many helpful suggestions 
and material aid from several persons. It was through Prof. Bourne 
that the writer was able to obtain specimens for dissection. The 
determination of hydrogen ion concentration by the electrical method 
was made by Dr. Itano using an apparatus devised by himself. For a 
fuller description of this device see Bulletin 167 of the Mass. Agricultural 
Experiment Station on the “Relation of Hydrogen Ion Concentration 
of Media to the Proteolytic Activity of Bacillus subtilis” by Arao Itano, 
January 1916. 
Dr. Holland kindly granted the use of the experiment station and 
both he and Mr. Dunbar demonstrated to the writer the methods em¬ 
ployed in arsenic determination. 
Miss Emma Oetinger very kindly prepared the manuscript for 
publication. 
To all these persons the writer wishes to express his sincerest grati¬ 
tude. 
RESULTS SECURED FROM LATE SEASON APPLICATIONS OF 
CALCIUM ARSENATE DUST, FOR THE CONTROL OF THE 
COTTON BOLL WEEVIL 
By C. B. Nickels, Clemson College , 5. C. 
Abstract 
The cotton boll weevil (Anthonomus grandis Boh.) causes severe damage to late 
fruiting crops after the beginning of migration. Serious injury did not occur in 
majority of fields until August 10th or later. 
The average increase in yield of seed cotton resulting from the use of calcium 
arsenate dust on comparable plots was 236 pounds per acre. Average expense of 
using the calcium arsenate dust method was the cost of 29.27 pounds of calcium ar¬ 
senate and 3.6 hours of labor. 
The experiments discussed in this publication were conducted in the 
Piedmont Section of South Carolina during 1923. During the season of 
1922, also 1923, a high percentage of the injury caused by the weevil, 
