14 BULLETIN 966, TJ. S. DEPARTMENT OF AGRICULTURE. 



attacks than topped shoes. This the writer demonstrated himself 

 many times. High-top shoes or, better yet, laced boots, gave a con- 

 siderable amount of protection. On several occasions the writer was 

 accompanied on his trips by Mr. W. W. Diehl, of the Bureau of 

 Plant Industry. Mr. Diehl demonstrated well how the body could 

 be protected by wearing topped shoes and spiral puttees. The latter 

 were wrapped tightly about the calves and gave almost complete 

 protection. 



Concerning this method, however, there are two objections: First, 

 it causes a considerable discomfort to wear such tight and rather 

 heavy clothing during the hot season, and second, if the individual 

 sits down, reclines, or brings the hands in frequent contact with the 

 surface of the ground, the chiggers will attack in considerable 

 numbers. 



Another method of gaining protection which has been tried in the 

 past is to use some repellent on the skin or on the clothing. Sulphur 

 has long been recommended for this purpose and Dr. Chittenden 

 (#, p. 5) calls it " a sovereign remedy for mites." A test of its 

 efficacy was made as follows : 



At East Falls Church, Va., on July 25, 1919, before going into a 

 well-known infested area, the left stocking and the lower part of the 

 underwear on the left leg were dusted inside and out with flowers 

 of sulphur. The sulphur was applied by the "pinch method," fol- 

 lowed by rubbing. About a tablespoonful was used. From 2.30 p. m. 

 to 4.20 p. m. there was exposure to attack in the infested area, and 

 at the end of this time a laboratory 7 examination was made. On the 

 calf and ankle of the untreated leg several chiggers were observed, 

 all unattached and running about very energetically. On the calf 

 and ankle of the sulphured leg not a single chigger was found. Later, 

 at 9.45 p. m., another examination was made. The untreated leg 

 had a large number of chiggers attached, these being distributed 

 from the ankle to the hip. The treated leg did not have a single 

 chigger attached. 



On August 4, 1919, a test was made to see if a dusting of sulphur 

 on both sides of the clothing was any more efficacious than dusting 

 on one side only. The stocking and underwear below the knee on 

 the left leg were sulphured by the " pinch method," both inside and 

 out. The stocking and underwear below the knee on the right side 

 were sulphured as before, but only on the outside. 



At 3.30 p. m., after exposure, an examination of both legs failed 

 to reveal a single chigger. It was noticed also that there was much 

 more sulphur adhering to the left leg than to the right. A later 

 examination at 11.30 a. m. the next day failed to reveal a single 

 chigger on the left leg and only one chigger wheal on the right, this 

 being near the instep of the foot. 



