34 



SCIENCE 



[N. S. Vol. XLIII. No. 1097 



tests as nearly under normal conditions as 

 possible. 



Agents Used. — The agents used fall into 

 three classes, namely: Powders not giving off 

 gas, powders that give off gases, and liquids. 

 Tests were run with sulphur, air-slaked lime, 

 paris green, naphthalene, gasoline, carbolic 

 acid, insect powder, tobacco stems and dust, 

 crude carbolic acid, 5 per cent, carbolic acid, 

 1 per cent, kreso dip, 2 per cent, kreso dip, 5 

 per cent, naphthalene in kerosene and 10 per 

 cent, formaldehyde. 



Sulphur. — Air-slaked lime was placed in the 

 bottom of a tumbler. At the end of 24 hours, 

 the mites had accumulated in a cluster in the 

 center of the dry lime. Upon being poured out 

 upon a paper they were still found to remain 

 vigorous. Dry air-slaked lime has apparently 

 no injurious effect upon them. 



Paris Green. — Dry paris green (powder) 

 was placed in the bottom of a tumbler and sev- 

 eral hundred mites placed in the powder and 

 stirred up. At the end of 48 hours the mites 

 had formed in a cluster in one edge of the 

 powder. Upon being removed they were found 

 to be as vigorous as before being placed in the 

 paris green. Dry paris green has apparently 

 no ill effect upon mites. 



Naphthalene (Powdered Moth Balls). — A 

 quantity of pulverized moth balls was placed 

 in the bottom of a tumbler and several hun- 

 dred vigorous mites placed on the surface. 

 At the end of 30 minutes motion was not so 

 active and at the end of 45 minutes all motion 

 ceased. Upon being removed and placed upon 

 paper all mites were found to be dead. 



Tohacco 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 

 among the tobacco. Frequent observations 

 were made and at the end of 72 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 1 part, and plaster of paris 

 sufficient to make a rather dry mixture. This 

 was passed through a sieve on to paper and 



after one hour was 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 Gent. Garholic Acid Solution in 

 Water. — A quantity of a five-per-cent. aqueous 

 solution of carbolic acid was poured out into 

 a saucer and several hundred mites placed on 

 one side, and the dish then tilted till all the 

 mites were wet, then the liquid drained from 

 them, the mites remaining on the wet surface 

 for observation. In 30 seconds all mites were 

 dead. 



One Per Gent. Naphthalene in Kerosene. — 

 One per cent, powdered moth balls dissolved in 

 kerosene was tested. A quantity of this fluid 

 was poured into a saucer and several hundred 

 mites placed on the opposite side of the saucer 

 then immersed as in the preceding test. In 

 30 seconds all mites in test were dead. 



Grude Garholic Acid. — Crude carbolic acid 

 was poured into a saucer and several hundred 

 mites placed on one side were immersed as in 

 the preceding test. In 20 seconds all mites in 

 the test were dead. 



One Per Gent. Kreso Dip. — This liquid was 

 poured into a saucer and several hundred 

 mites subjected 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 Gent. Kreso Dip. — Test conducted 

 as the preceding. At the end of two minutes 

 motion was retarded and all mites in the test 

 were dead at the end of four minutes. 



Ten Per Gent. Formaldehyde. — The test was 

 conducted as in the preceding. At the end of 

 ten minutes all the mites in the test were dead. 



Summary 



Duplicate tests were run to determine the 

 action, if any, of powdered sulphur, air-slaked 

 lime, paris green and naphthalene upon the 

 Tronibidium holosericeum (the chicken mite). 



It was found that though sulphur in solu- 

 tion as in lime and sulphur dip is an efficient 

 parasiticide, that although paris green in solu- 



