DR. LEGEAR'S STOCK BOOK. 299 



surface of l he water three-fourths to one inch in depth. The 

 cattle were forced through the chute and plunged into the vat. 

 On rising to the surface and coming out they became covered 

 with oil, which was exceedingly fatal to the tick without causing 

 ;:ny positive injury to the cattle. We noted, however, that such 

 ;i coating of oil in the vat soon became greatly altered in appear- 

 ance and quality, from contact with the water, which eventually 

 induced us to seek a substitute. We next tried a cheap natural 

 or mineral oil, called "Winter West Virginia." We used this in 

 the same manner as the cotton oil. It bears agitation with water 

 quite well, but it occurs to me that it is not so fatal as the cot- 

 ton oil to the tick. We sometimes use it alone, and sometimes 

 add carbolic acid to it. In some instances we have dipped a 

 bunch of cattle with absolutely perfect results, and sometimes we 

 notice an animal on which the work was imperfect. There is 

 yet a third condition of affairs for which we have no satisfactory 

 explanation. It sometimes occurs that half-grown ticks will be 

 noticed several days after dipping. This has caused us great an- 

 noyance and much study. At present we attribute it to the con- 

 dition of the tick at the time of dipping, viz., that it was moult- 

 ing. These young ticks sometimes increase in size, and may 

 have the appearance of healthy ticks, but we have invariably 

 failed to hatch their eggs, w^hich seem to have been aborted, 

 though the conditions were suitable as proven by eggs of other 

 ticks hatching under the same conditions. This has led us to be 

 somewhat guarded of late, in claiming that one dipping will 

 offer sufficient safeguard against Texas fever, if the dipping pro- 

 cess be adopted on a commercial basis. For purety experimental 

 I mi-poses it may, but in our judgment it would be somewhat- 

 risky for general use. It occurs to us then, that if a change in 

 the present Federal regulations be contemplated, it would be 

 wise to require two dippings with an interval of several days. 

 This we believe would be absolutely safe." 

 20 



