TABLE 4.--Summary of studies of the oral toxicity of herbicides to sheep 
and cattle at Kerrville, Tex. 
. Fre- 
Me. /kg.° 
Pentachlorophenol Sheep 25 1dose mild toxicity 
Cattle 2) i dose mild toxicity 
(Delrad) Dehydroabietylamine acetate Sheep 250 1 dose tolerated, higher 
doses toxic 
Cattle 200 1 dose tolerated, higher 
doses toxic 
Dinitro-o-sec-butyl phenol Sheep >) daily death after 4 doses 
Alkanolamine salts of Dinitro-o-sec-butyl Sheep 25 daily tolerated 35 doses* 
phenol 
2-(2,4,5-Trichlorophenoxy) propionic acid, Sheep 100° daily lethal after 11 
propylene glycol butyl ether esters doses 
2-4-Dichlorophenoxyacetic acid, Sheep 100° daily tolerated 35 doses* 
alkanolamine salts 
2,4,5-Trichlorophenoxyacetic acid, Sheep 100 daily tolerated 35 doses* 
alkanolamine salts 
2,4-Dichlorophenoxyacetic acid, propylene Sheep 100 daily tolerated 35 doses* 
glycol butyl ether esters 
2,4,5-Trichlorophenoxyacetic acid, Sheep 100 daily tolerated 35 doses* 
propylene glycol butyl ether esters 
2,4,5-Trichlorophenoxyacetic acid, Sheep 100 daily tolerated 35 doses” 
triethylamine salts 
2,2-Dichloropropionie acid, sodium salt Sheep 100 daily tolerated 35 doses™ 
*At time of preparation of this table, these tests were in progress. 
Pesticides prepared in granular form for many uses accomplish their objective 
more effectively; yet, because of the weight of the granules, the amount remaining on 
foliage or drifting away from the area is greatly reduced. 
Biological Cycles 
To a certain extent we have biological cycles involved in the use of pesticides. For 
example, we may treat a body of water for insect control and accomplish the objective, 
but organisms not killed by the treatment may absorb and store the chemical. They, in 
turn, according to their biological position, may be consumed as food by other species, 
and these in turn by others, until there is ultimately a removal from that water ofa 
species serving as food for mammals or birds, or man, The cycle is then continued out- 
side the original environment. 
The accumulation of pesticide may be attenuated or concentrated within this cycle, 
depending upon the part the animal or plant may provide of the total diet of the consum- 
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