June, 1917.J ARSENICAL RESIDUES AFTER SPRAYING. 49 



lead paste containing 50 per cent water per calf per day, so far 

 as the amount of material applied to the grass is concerned. 



Where the material was used at the rate of 6 lbs. of arsenate 

 of lead paste to 50 gallons of water, the calves consumed most 

 of the grass in the two plots within a period of 10 days. To this 

 grass was applied arsenate of lead, representing 37.8 grams of 

 arsenic oxid AS2O5 or 18.9 grams for each calf or 1.9 grams per 

 calf per day. This is approximately 5.7 grams of dry arsenate 

 of lead or 11.4 grams of arsenate of lead paste, containing 50 per 

 cent water per calf per day, so far as the material applied to the 

 grass is concerned. 



Where the material was applied at the rate of 10 lbs. of arsenate 

 of lead paste to 50 gallons of water the two calves did most of 

 their feeding in the first 4 days. To this grass was applied 

 arsenate of lead representing 31.5 grams of arsenic oxid AS2O5 or 

 15.7 grams per calf or 3.9 grams per calf per day. This is the 

 equivalent of 11.7 grams of dry arsenate of lead or 23.4 grams of 

 arsenate of lead paste per calf per day so far as the material 

 applied to the grass is concerned. 



Comparing now the results recorded by Paige (13) in experi- 

 ments conducted at the Massachusetts Agricultural Experiment 

 Station in 1907. In these experiments 5 cows condemned as 

 tubercular were used. To these cows arsenate of lead was 

 administered with their food, in varying amounts and with vary- 

 ing results. Twenty-nine consecutive doses of 1 gram of arsenate 

 of lead paste per day administered to cow No. 1 was followed 

 by the death of the cow on the forty-first day. An autopsy dis- 

 closed extensive tubercular lesions. To another cow .5 grams 

 of arsenate of lead paste was administered for 33 consecutive 

 days and the animal was killed at the end of 37 days. Again 

 an autopsy showed serious tubercular lesions. The question 

 arises whether the symptoms of poisoning observed in these 

 cows. may not have been accelerated by their physical condition. 

 To 3 other cows varying amounts of arsenate of lead paste were 

 administered, ranging from 2 grams to 56.7 grams. In some 

 instances the smaller doses resulted in symptoms of poisoning 

 but in another case after administration of varying doses a single 

 dose of 50.4 grams was administered to a cow without fatal 

 effects. 



It is interesting in comparison to note the results found by 



