74 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 9 



cent of the ticks from the wool, but when picked up and kept in a vial, 

 they revived in about twelve to twenty -four hours. Those left in the 

 wool did not revive. Even though the ticks might not be killed with 

 this exposure, by removing them to the floor of the box, one could 

 easily destroy them later,, by spraying the floor with some strong sheep 

 dip. This is of particular value as sheep in wool cannot be successfully 

 dipped. The fumigation did not kill the puparia. Chickens were 

 fumigated and it was shown that, in eight to ten hours, all the lice on 

 the chicken could be destroyed. In a chicken house which was fumi- 

 gated the red mites were also killed. The mite causing scaly leg of 

 chickens can also be destroyed by a ten-hour fumigation. The Texas 

 cattle fever tick cannot be obtained in Minnesota on the animals, but 

 specimens received from the South and fumigated in glass vials were 

 killed by a ten-hour exposure. Most of the specimens of ticks were 

 fully engorged females laying or about ready to lay their eggs. One 

 case of interest was that of a female which had started laying, probably 

 having laid a quarter of her usual number at the time of fumigation. 

 The tick was killed by the fumigation and no further eggs were laid. 

 It might be noted that the engorged female ready to lay or laying, is 

 probably the most difficult to destroy. 



The Effect of Nitrobenzene on the Animal 

 So far as could be noticed, the animals showed no signs of poisoning 

 under normal conditions. They all fed readily when removed from 

 the box, and when compared with normal animals, were indistinguish- 

 able. A dog fumigated for six hours was normal in heart beat, res- 

 piration, and temperature. A count of the red blood corpuscles of a 

 guinea pig before fumigation and after fumigation showed little change. 

 Five million four hundred thousand red corpuscles per cu. mm. were 

 obtained before fumigation. After fumigation for 12 hours and a half 

 the blood count obtained showed 6,040,000. Twenty-four hours later 

 showed 6,320,000. In 48 hours, 5,840,000. Such sUght differences 

 might well be obtained by experimental error in the count. In order 

 to determine whether nitrobenzene would have any injurious effect 

 upon the animal when repeated a number of times, guinea pigs were 

 obtained and divided into two groups, a fumigated set and a normal 

 set. Each set contained one full-grown male, one young male, one 

 full-grown pregnant female, and a litter of young, the mother of which 

 was not fumigated. The one set was fumigated over night, the expos- 

 ure varying from 12 to 13 hours and repeated each week. 



When the pregnant female in the fumigated set gave birth to her 

 young, they were fumigated along with the mother animal. The old 

 males remained normal, varying slightly from week to week. The 



