16 BULLETIN 131, IT. S. DEPARTMENT OF AGEICULTUEE. 



OIL OF TAR.i 



TEN PER CENT OIL OF TAR IN COTTONSEED OIL. 



July 22, 1912, sprayed a calf with 10 per cent oil of tar in cotton- 

 seed oil. Used about 2 quarts of the mixture. 



July 23, the oil was still evident. No hornflies were observed. 

 Stable flies were seen to light on the hair but left immediately. Some 

 stable flies were seen on the legs of the animals. 



July 25, the odor of the oil of tar had entirely disappeared. The 

 hair was still oily but flies were seen to light on the oily spots. 



July 29, there was no oil present. 



July 15, 1913, applied 3| ounces of the mixture to a calf by means 

 of a brush. The repellent action was very marked. 



July 16, about 18 hours later, the calf did not fight the flies quite 

 so much as did the controls. There was no odor of tar. There was 

 a very slight evidence of oil on the sides and back but no repellent 

 action could be observed. 



HALF-AND-HALF MIXTURE OF OIL OF TAR AND COTTONSEED OIL. 



August 22, 1912, sprayed a calf with a half-and-half mixture of oil 

 of tar and cottonseed oil. Used about 2 quarts of the mixture. The 

 animal almost immediately began to show signs of sickness. The 

 eyes were half closed. The skin about the eyes, on the face, and at 

 the corners of the mouth was wrinkled. There was slight salivation. 

 These symptoms were followed by a slight swaying in the hind quar- 

 ters when the animal walked. Finally the gait became staggering 

 and the animal fell from time to time and arose again only with the 

 greatest difficulty. 



August 26, when the next observation was made, the animal had 

 entirely recovered. There was no repellent action noticeable. 



TEN PER CENT OIL OF TAR IN BEAUMONT OIL. 



July 22, 1912, sprayed a calf with 10 per cent oil of tar in Beau- 

 mont oil. Used about 2 quarts of the mixture. 



July 23, oil was present on the hair. There were a very few stable 

 flies on the legs. No hornflies were observed. 



July 25, more oil was present on the hair than in the case of a 

 calf sprayed on the same date with a mixture in which cottonseed 

 oil served as the base. 



July 29, oil was present on the back and rump. No hornflies were 

 observed. 



1 A sample of the oil of tar used in these experiments was examined in the Biochemic 

 Division of the Bureau of Animal Industry and was found to contain phenols, volatile 

 with steam, 14 per cent. 



