6 BULLETIN 875, U. S. DEPARTMENT OF AGRICULTURE. 



three and can be avoided very easily by careful washing of the hands 

 and face before eating or drinking. 



Inhalation is a danger which is constantly present and is difficult 

 to avoid except by the use of dust masks or some type of filtering 

 arrangement which removes the dust from the air entering the mouth 

 and nostrils. 



Absorption undoubtedly is a very important means of taking 

 arsenic into the human body. Even if extreme precautions are taken 

 during dusting operations to avoid excessive direct contact with the 

 poison supply, there is still a very considerable amount of poison 

 dust settling all over the body from the air. This also has a decided 

 tendency to adhere to the skin and " shed " water unless a strong 

 lather is utilized, so a hasty rinsing in clear water should not be con- 

 sidered as a satisfactory means of removing the poison. 



The danger of poisoning, although slight, should be considered. 

 In the work conducted under the direction of the writers large 

 quantities of calcium arsenate have been used by all sorts of laborers 

 and generally with extreme carelessness. In spite of this, however, 

 very few definite symptoms of even the slightest arsenical poisoning 

 have been observed in connection with the field operations, and these 

 few undoubtedly would have been avoided if proper precautions had 

 been taken. Anyone using dry powdered calcium arsenate need not 

 fear poisoning if he is reasonably cautious, but if any unexplained ill- 

 ness should develop during its use the possibility of poisoning should 

 be borne in mind and a physician consulted. The preliminary symp- 

 toms of arsenical poisoning differ widely, but generally involve an 

 intestinal and digestive disorder and are usually accompanied by 

 some form of skin eruption. 



An additional indirect danger to live stock should be considered. 

 The cloud of poison frequently has a tendency to drift considerable 

 distances. Conditions may be such that a dangerous amount of 

 poison will drift into a neighboring pasture and injure some of the 

 stock feeding on the grass. Stock should certainlv not be allowed 

 to graze on headlands and turnrows in fields which are being poi- 

 soned. The same applies to chickens, turkeys, and other fowls. The 

 only fatalities the writers have observed in the course of poisoning- 

 work have been in the case of chickens and turkeys running in 

 poisoned fields and picking in the debris covered with a heavy dos- 

 age of poison, where the machine had stopped and covered the ground 

 rather thoroughly. 



PLANT INJURY BY CALCIUM ARSENATE. 



It is well to explain briefly the usual nature of arsenical injury 

 to cotton plants, as there is a tendency on the part of inexperienced 



