117 



Graybill (H. W'.). The Action of Arsenical Lips in Protecting 

 Cattle from Infestation with Ticks. — U .S. Dept. Agric, Bureau 

 of Animal Industrjj, Bull. 107, 15tli April 1913, 27 pp. 



Dips act both in a directly destructive way and in a protective 

 manner by preventing' infestation. The protective action of a dip 

 may be destructive or repellent. The influence of dips on ovi- 

 position and the viability of the eggs is a factor in eJhcacy. The 

 ingredients of home-made arsenical dips and the known or pro- 

 bable function of each ingredient are discussed. It is suggested 

 in the bulletin that any protective action that the usual arsenical 

 dips miglit have would be expected to be due to a toxic rather 

 than to a repellent action. Watkins-Pitchford has shown that 

 cattle dipped in arsenic are poisonous to ticks. Ticks are 

 destroyed by dips either by suffocation or by poisoning, or by both 

 means. Tests were conducted showing that ticks are suffocated 

 by the closing of the spiracles, Canada balsam causing death very 

 soon, while Beaumont oil proved less effective, and cotton seed oil 

 was practically without effect. Smearing the scutum and mouth 

 parts of engorged females with oils and viscous substances had 

 no influence on the mortality, or oviposition, or on the percentage 

 of eggs hatching. Beaumont oil had a marked influence on the 

 number of eggs deposited and on the viability of the eggs, whereas 

 cotton seed oil had no effect. 



Three cattle-dipping experiments were conducted with an 

 arsenical dip containing 8 pounds of arsenic trioxide to 500 

 gallons of water, in order to test its protective action against tick 

 infestation. Seed ticks were placed on the cattle in the first 

 experiment at periods ranging from a few hours to four weeks, 

 in the second from a few hours to two days, and in the third at 

 five days after dipping. It was found that the dip rendered no 

 protection Avlien the exposure to infestation was five days or 

 longer after dipping. The limit of protection ascertained in the 

 experiments was two days. Arsenical poisoning which occurred 

 among the calves in one experiment was apparently caused by 

 undissolved arsenic in the dip (white arsenic does not dissolve 

 readily unless the water be kept boiling). 



As a result of incidental observations made on engorged female 

 ticks from animals suffering from Texas fever it was found that 

 the mortality of such ticks varied from 40 to 95 per cent, and 

 was higher among those taken from the undipped control animal 

 than those from the dipped animals. It is known that the 

 mortality among ticks taken from animals suffering from Texas 

 fever is abnormally high, so that the results are somewhat incon- 

 clusive as to the part played by the arsenical dip. 



Eroxtowski (Dr. A.). Zur Frage iiber die Typhus- und Dysenterie- 

 verbreitung durch Fliegen. [On the dissemination by flies of 

 typhus fever and dysentery.] — Centralhlatt fur Bakteriologie, 

 Parasitenkunde und Infektionshrankheiten, Jena, Ixviii, 

 no. 7, 23rd April 1913, pp. 586-590. 



Larvae of Sarcophaga carnaria, Lucilia caesar, Sarcophaga 

 (Cynomyia) mortuorum, and Musca domestica were infected with 

 Bacillus typhi and B. dysenteriae and allowed to pupate. An 

 (30546—2.) Wt. P 11—12. 2000. 7/13. D & S. 



