184 EXPERIMENT STATION. [Jan. 



mals that ate the grass taken from under trees that had been 

 sprayed with a strong mixture of arsenate of lead. The experi- 

 ment consisted in taking sufficient grass for two large feeds for 

 a horse and spreading it under a pear tree that was later sprayed 

 with a liberal quantity of arsenate of lead, in the proportion of 

 20 pounds to 150 gallons of water. Not satisfied that the 

 amount of the mixture dripping from the tree on the grass was 

 sufficient to make the test conclusive, the grass was thoroughly 

 drenched with the mixture direct from the nozzle of the spray- 

 ing machine. The treated grass was fed to a 1,200 or 1,300 

 pound horse during the afternoon and evening of the same day 

 that it was sprayed. Two days later the animal was found to 

 be well and hearty, and reported by the teamsters to be in better 

 condition than before the grass had been eaten. The burning 

 effect of the sjDray upon the foliage of the pear tree proved that 

 there was considerable soluble arsenic present, which would 

 render the arsenate of lead much more poisonous to animals than 

 a properly prepared arsenate of lead that contained but little 

 soluble arsenic. 



During the past two or three years, since the revival of the 

 gypsy moth work in the eastern part of the State, numerous 

 letters received at the experiment station, as well as newspaper 

 articles and reports from veterinarians, have suggested that 

 farm animals were being poisoned from the ingestion of grass 

 and foliage of shrubs sprayed with arsenate of lead, used in the 

 destruction of the gypsy moth. 



To determine whether or not this was the case the experiment 

 station began a series of experiments in 1907 to ascertain what 

 effect arsenate of lead would have upon cattle when given in 

 small doses for a long time or when given in large single doses. 



The cattle used in the experiment were animals that had been 

 condemned as tuberculous by the inspectors of the Cattle Bureau 

 of the State Board- of Agriculture. These were placed at the 

 disposal of the experiment station by the courtesy of. Dr. Austin 

 Peters, Chief of the Cattle Bureau, and were in every instance 

 subjected to a careful post-mortem examination, to note the 

 effects of the arsenate of lead and to determine whether or not 

 tuberculosis was present. 



The arsenate of lead used in the experiment was manufac- 



