198 EXPERIMENT STATION. [Jan. 



151 grams in 2, 3 and 4 gram doses daily before equally marked 

 symjDtoms of poisoning appeared. With No. 4, 28.35 grams 

 given at one dose in capsule at 9.45 a.m. produced toxic effects 

 in less than twenty-four hours, from which the animal did not 

 recover completely for six or seven days. In the case of No. 5, 

 56.70 grams caused death in sixty-nine and one-half hours. A 

 study of the records of the five animals shows that frequently 

 repeated small doses of the arsenate have the same effect in the 

 end as do large non-fatal doses given at one time. In feeding the 

 lead arsenate paste it was found necessary to adopt every con- 

 ceivable means to induce the cows to take it after a few doses 

 had been given. At first when mixed with the hay or grain it 

 "was readily eaten, but after a short time the animals would care- 

 fully separate every particle of the paste from the hay or grain 

 and leave it uneaten. It was for this reason that it was found 

 necessary to conceal it in capsules enclosed in j)ieces of roots 

 to insure its being eaten. When the hay that had been drenched 

 with 1 and 2 ounces of lead arsenate in water was allowed to 

 hecome thoroughly dried, it was readily eaten by the cows that 

 had previously refused the fresh paste, even when thoroughly 

 mixed with hay and grain, or enclosed without capsule inside 

 of pieces of roots and api^les. The fresh arsenate had an odor 

 of acetic acid that was not noticeable in that contained in the 

 dried hay. 



To determine approximately how much hay would become 

 covered with the drip in the spraying of a medium-sized tree 

 the grass was cut on an area 35 feet in diameter under a tree 

 near the veterinary hospital, thoroughly hayed and weighed. 

 It was a moderately heavy growth of herds grass and weighed 

 when dried 50 pounds. Allowing for a drip of 1 gallon in 10 

 of a mixture of 10 pounds of the arsenate to 100 gallons of 

 water, each 10 pounds of the total of 50 would carry 9.06 grams 

 of the arsenate j)aste, or practically one-half of that amount of 

 the dried arsenate. 



It would hardly be expected, taking into consideration the 

 results obtained by feeding carefully weighed amounts of the 

 arsenate, that a 10-pound feed of such hay would produce serious 

 effects, but the continuous feeding of it for several days in suc- 

 cession would certainly do so, and judging from the experience 



