BOLL WEEVIL CONTROL BY USE OF POISON. 5 
KEEPING QUALITIES OF CALCIUM ARSENATE. 
Questions frequently are received as to whether or not calcium 
arsenate will deteriorate during long periods of storage. In some 
cases farmers purchased more than they could use during the past 
season and desired to hold over their surplus stock for use during the 
coming year. This is perfectly safe, as a properly made calcium 
arsenate should not deteriorate if stored in a reasonably dry place. 
Some lots have been kept at the Delta Laboratory for four years 
under normal storage conditions without the slightest deterioration. 
Moisture, however, even when it does not induce chemical deteriora- 
tion, will cause calcium arsenate to cake so badly that it can not be 
utilized in the dusting machines. 
EFFECT OF THE POISON ON MAN AND ANIMALS. 
Questions are frequently asked regarding the effect of calcium 
arsenate on laborers and mules engaged in the poisoning operations. 
It is not nearly as dangerous as Paris green, as it does not have the 
caustic action characteristic of the latter. There is, however, a cer- 
tain amount of danger attendant upon the use of any arsenical com- 
pound and reasonable precautions should be taken to protect the 
men and animals associated with it. Inhaling the dust should be 
avoided as far as possible. The most important precaution is that of 
personal cleanliness when using the material. The operators should 
be forced to bathe as soon as they complete the dusting work, and 
they should not be permitted to eat anything without at least wash- 
ing their hands and face thoroughly. No injury to work stock has 
ever been experienced during operations, but, it is safest to keep ordi- 
nary wire muzzles on all such animals in the poisoned fields. 
The question of fall grazing of poisoned cotton fields is frequently 
raised. As a rule the last application of poison is made at least a 
month, and usually two or three months, before the cotton crop is 
harvested and the animals allowed to graze on the cotton fields. 
Even if no rains have occurred to wash the poison from the plants ~ 
during this period, the amount of leaf shed has been so great that 
the foliage of the plant has probably been renewed several times and 
the plants utilized for grazing purposes are largely, if not entirely, 
new growth. 
With regard to the danger to man involved in the use of calcium 
arsenate in the form of a dust cloud, it should be understood that 
arsenic may be taken into the body in three ways—by the mouth, 
by breathing, and by absorption through the skin. Ingestion or 
swallowing is the only manner which usually receives serious con- 
sideration, but in all probability it is the least important of the 
