' THE AGRICULTURAL NEWS. 



How Ticks are Killed 



When Cattle 

 Are Dipped or Sprayed 



CATTLE TICK 



A knowlcJoe of how a dip it &bsorbe<l by Ticks when cattle are dipped or spr&yed >%'ith an iirsenical \vai)i is of great assistance in elucidating the 

 problem of Ti.k destruction. Although this subject has given rise to much conjecture, ^'c^^- little definite information is obtainable as a result of practical 

 experiment. Work directed by ^X'illiam Cooper and Nephews in South Africa has, however, furnished results from which feasible deductions ha>e been 

 made, and these appear to throw some Tight on the subject. 



The theories advanced by different workers arc : — 



1 . That the Tick absorbs the poison through its own skin during ihe process of dipping or spraying. 



2. That the absorption of the poison through the skin of the Tick lakes place after the operation of dipping or spraying is completed. 



3 That the poison is absorbed bj the skin of the animal, and that the Tick sucks in the poison with the fluids extracted while feeding on 

 the animal. 



It follows from No. I theory, and it is asserted by those who favour this theory, that the longer the period of immersion of the animal in the tick-killing 

 fluid, the more certain is the destructive effect on the Ticks. For lliis reason the supporters of this theory advocate a dipping bath with a long swim. 



As i result of the work carried out under the direction of William Cooper and Nephews, it has been established that a brief, thorough immersion of 

 the animal kills the Ticks as effectively as a long one. That is to say, complete immersion for a comparatively short time, ensured the death of the Ticks. 



If Ticks are taken off cattle soon after they have been dipped or sprayed with an arsenical \vash, and are thoroughly cleaned to remove any exlern.il^y 

 adherent arsenic, their bodies are found to contain no traces of the poison, whilst Ticks similarly removed on each of the six days following dipjiing ©re 

 'found to contain appreciable quantities of arsenic, thus proving that the arsenic is absorbed after the operation of dipping or spraying is completed. 



\X'ith regard to theory No. 2, it is highly improbable thdt the arsenic is absorbed through the skin of the Tick, for the fluid dries on the skin in less 

 :lhan an hour after treatment, during which period, as was shown in the previous paragraph, no absorption takes place. 



There only remains then theory No. 3, v/z., that the host animal absorbs the poison into its skin, and later the Tick imbibes the poison during the 

 process of feeding. All experience with dips in the 6eld goes to support this theory. 



' Given dips which contain equal amounts of the poisonous agent, it has been proved by actual cxperiaMM that those which spread over and thoroughly 

 ;wet the whole surface of the skin of the animal possess the greatest killing power. Therefore, an essential feature of a dip is that it should give complete 

 'and uniform penetration over the whole skin tnrfaoe of the animal. . 



It is a proven fact that those dips which tatarale the skin in patches kill only the Ticks which aifliere to ikoae patches. It is found, moreover, that if 

 'a scluilon of arsenic is injected subculaneously, the Ticks attached around the site of the injection are poisoned, and although they have h.id no coniact 

 with arsenic from the exterior, their remains are found to contain appreciable quanlitiet. This poisonous action is limited to an area of about 6 inches radius 

 :from the site of inoculation. 



Investigations have shown that arsenic applied to the undamaged skin of an animal does not appear in appredable quantities in the internal organs of 

 the body. This seems to prove that the arsenic which is absorbed by the skin fails to reach the circulating blood which would carry the poison from the 

 tarface to the interior. The accumulated facts which have resulted from enquiries into the matter lend the greatest support to the theory that the ll\ing 

 cells, which form the deeper layers of the skin, have an actual affinity for arsenic, and the poison is arrested and fixed in them and thus prevented from 

 reaching the circulating blood. If this theory is correct, then after dipping or spraying, the deeper layers of the skin will become strongly impregnated 

 with arsenic, possibly in a state of combination with the organic tissues. It i^ then easy to suppose that while feeding on a beast which has been rececdy 

 dipped or sprayed, the tick takes in considerable quantities of the poison with the blood and lymph which have necessarily passed tbrough these deeper 

 iHrers of the skin, which are more or less saturated with arsenic. 



COOPER'S CATTLE TICK DIP 

 Hat neeiotd the official approval of the following CoantriM t 

 UaloD 0) South Africa, Northern Khnilcsia, Brazil, Hasutoland, 



Nyataland, Swazilaail, Soulbern Rhodesia, ^l.'lJ.l^&scIIr, 



BrIlUh ra«l .Africa, Qcrman East Africa, Portuguese Past Afrlci, 



Portu|uete West Africa, Egypt, Argentine Kcpubllc, Qucenslaatf, 



United Stales of America, New South Wales, 



■^ Northern Territory of Australia. 



WEST INDIAN AGENTS; 



•T'KITTAi a. L. HorstnrdAC*. ANTIQUA: Bennett, llryaos « Ca. 



JAMAICA! D. Hmdersoo ft Co., Kiosraton, 



UKGNADAi Thomson, linnkcy ft Co. 



IIAKBAD05: Barbadoj Co-oreratlve Cotton Co.. l.tiL 



ltMtA.MA5: W. N. Twynom. Na.vuu. 



TRIMDAI): T. Oeddes Urant. t>urt o( .5pain. 



BRiriStI QUtANA: 3iuidbacli, >>arker ft Co. 



rrr. VINCENT: Corca ft Co., Klntatown. NtiViS: .s. n. Malone. 



DANISH WBST INDiaS: Carl V. La Beet, 5t. Tlioniu.s. 



MONTSBRRAT: W. UeweUyn Wall. DOMI.MCA: Hon. H. A. Framptoa. 



5T. t.UCIA: Barnard 5ods & Co., Cn.strlcn. 



Manufacturers : WILLIAM COOPER & NEPHEWS, Berkhamsted, England. 



EftANCHES : Toronto, Chicago, Sydney, Mdhoanie, AucUaad, Buenos Aim, M«i.t< Video, Puata Artaat, East London, Odessa. 



