78 POULTRY DISEASES 



minutes motion was not so active and at the end of forty-five 

 minutes all motion ceased and upon being removed and placed upon 

 paper all were found to be dead. 



Tolxicco Bits. — Bits of tobacco leaves, the sweepings from the 

 floor of a tobacco factory, were placed in the bottom of a tumbler 

 and several hundred very active mites placed in the tobacco. Fre- 

 quent observations were made and at the end of seventy-two hours 

 the mites were as active as when they were placed in the tumbler. 



Insect Powder. — A powder prepared in this laboratory consists of 

 gasoline three parts, crude carbolic acid one part and plaster of 

 paris sufficient to make a rather dry mixture. This was passed 

 through a sieve onto paper and after one hour placed in tight jars 

 till needed. A quantity of this powder was placed in the bottom 

 of a tumbler and several hundred active mites placed in the material 

 and mixed with it. At the end of one minute all mites were dead. 



Five Per Cent Carbolic Acid Solution in Water. — A quantity of 

 a five per cent aqueous solution was poured out into a saucer and 

 several hundred mites placed on one side and the dish then tilted 

 till the mites were all wet, then the liquid drained from them, the 

 mites remaining on the wet surface for observation. In thirty 

 seconds the movements were retarded and at the end of sixty sec- 

 onds all mites were dead. 



One Per Cent Naphthalene in Kerosene. — One per cent powdered 

 moth balls dissolved in kerosene was tested. A quantity of this 

 fluid was poured in a saucer and several hundred mites placed on 

 the opposite side of the saucer, then immersed as in the preceding 

 test. In thirty seconds all mites in the test were dead. 



Crude Carbolic Acid. — Pure crude carbolic acid was poured in a 

 saucer and several hundred mites placed on one side, were immersed 

 as in the preceding test. In twenty seconds all mites in the test 

 w^ere dead. 



One Per Cent Kreso Dip. — This liquid was poured in a saucer and 

 several hundred mites subjected to a bath as in the preceding tests. 

 At the end of four minutes motions slowed and at the end of ten 

 minutes all mites in the test were dead. 



Two Per Cent Kreso Dip. — The test was conducted as the preced- 

 ing. At the end of two minutes motion was retarded and all mites 

 in test were dead at the end of four minutes. 



Ten Per Cent Formaldehyd. — The test was conducted as in the 

 preceding. At the end of ten minutes all the mites in the test were 

 dead. 



Pyrethrum. — Lice covered with pyrethrum powder were rendered 

 inactive in six to ten minutes. 



A pow^der prepared in this laboratory as follows killed lice in 

 thirty seconds: Nicotine V4 ounce, naphthalene 1 ounce, standard- 

 ized coal tar disinfectant dip 4 ounces. Sufficient plaster of paris 

 was mixed with it to make a slightly moist mixture and this passed 

 through a fly screen and used at once. 



There was also tried the following mixture: Nicotine (aqueous 

 solution containing 40 per cent nicotine) solution 40 minims, water 

 4 ounces, plaster of paris 1 pint. As soon as these substances 

 are mixed together they heat, due to the plaster of ])aris being 

 converted back to gypsum. During this heating process the powder 

 must be occasionally stirred. This powder kills lice in 30 seconds 

 and has been found still effective after being prepared 7 months. 

 The sulphate of nicotine is also effective. 



It was found that though sulphur in solution is an efficient para- 



