50 N. H. AGR. EXPERIMENT STATION. [Bulletin 183 



Haywood (10) in studies of the arsenic content of forage at 

 Anaconda, Montana, near a smelter giving off daily large amounts 

 of volatile arsenic. Analyses showed water-soluble arsenious 

 oxid ranging from 0.16 grams to 0.94 grams per 25 pounds of 

 dried forage. Similarly, Harkins (Formad 5) in the same locality 

 found arsenic present in amounts ranging from 0.1 to 8.0 grams 

 per 25 pounds of forage. Live stock had suffered severely in the 

 neighborhood. It should be observed, however, that the effects 

 may quite probably have been due in part to volatile arsenic 

 entering the lungs. In fact this is indicated by the findings of 

 Formad (5) whose post-mortems of animals from the region 

 showed usually congested lungs and trachea as well as ulcerated 

 nostrils. 



So far as our own experiments are concerned, they appear to 

 indicate that healthy calves may be pastured for a period on 

 grass carrying considerable spray when the strength of solution 

 used is 3 lbs. of arsenate of lead paste to 50 gallons of water. 

 When the concentration of spray material is increased to 6 lbs. 

 of arsenate of lead paste to 50 gallons of water continued feeding 

 on such grass may result in definite and serious symptoms of 

 poisoning. With the concentration at 10 lbs. of arsenate of lead 

 paste to 50 gallons of water, serious or fatal poisoning is likely to 

 result. 



SHEEP. 



The first set of experiments with sheep followed the plan of 

 those carried out with calves and described above. Movable 

 pens were used, each enclosing a space measuring 25 feet each 

 way, or 625 square feet. These pens were set up in an orchard 

 in which there was a fairly uniform growth of grass 6 to 8 inches 

 high. The sheep were grade ewes of practically uniform weight, 

 condition and health. When a pen was set up the grass within 

 it was sprayed with 2 gallons of spray material. This amount of 

 material was used because, as noted above, it appeared to be the 

 maximum that would cling to the grass in the area indicated, this 

 area representing the space beneath a large tree. Sprays of three 

 different concentrations were used; namely, the equivalents of 3 

 lbs. of arsenate of lead paste to 50 gallons of water, 6 lbs. to 50 

 gallons and 10 lbs. to 50 gallons. As soon as the sheep had 

 eaten all of the grass within a pen, sheep and pen were moved 

 to a new plot prepared as before. 



