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OHIO EXPERIMENT STATION: BULLETIN 356 



chicken lice. Prior to this work its only known insecticidal use was 

 against cockroaches, for which it has been demonstrated to be high- 

 ly effective. 



In December, the flockmaster at the Ohio Agricultural Experi- 

 ment Station reported that the ewes were rubbing themselves and 

 pulling out their wool. An examination of the taggiest of the ewes 

 showed a heavy infestation of red-headed lice to be the cause of the 

 unrest. As these ewes had been dipped 2 years before, the lice 

 probably had been introduced into the flock by an imported ram. 

 The importance of using protective measures in the case of every 

 new addition from outside sources in therefore emphasized. 



Dusting a sheep with a plunger gun. 



There were 102 ewes in the flock. To treat each of them with 

 powder seemed an endless operation. However, it was necessary 

 to check the ravages of the lice. So sodium fluorid was tested on a 



