THE AGRICULTURAL NEWS. 



How Ticks are Killed 



When Cattle 

 Are Dipped or Sprayed 



e*TTUE TtOK 



A Icnowlcdge of how a dip U absorbed by TicU when caltle are dipped ur ipnjreJ with an arsenical wash is of great a^slstsncc in elucidating the 

 problem of Tick destruction. Although this subjeci has given rise to much conjecture, very little definite information is obtainable as a result of practical 

 experiment. Work directed by ^X'!i!iam Cooper arid Nephews in South Africa has, however, iLmisIied results from \\'luch feasible deductions have been 

 made, anJ vb?'e appear !o throw some light or. the si;bjecl. 



The theories adtanccd by different woilers are : — 



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



2. Th^t the absorption of the poison through the skin of the Tick takes place after the operation of dipping or spraying is completed. 



3 Th^l the poison is absorbed by the skin of the animal, and that the Tick sucks in the poison with the fluids extracted while feeding on 

 the animal. 



It follow 5 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-kilUng 

 fttid, thw more certain is the deslruclive eiF^ct on the Ticks. For this reason the supporters of this theory advocate a dipping bath with a long swim. 



A? a result of the work carried out under the direc'.ion of William Cooper and Nephews, it has been established that a brief, thorough immersion of 

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



If Ticks are taken off cattle soon after they have been dipped or sprayed with an arsenical wash, and are thoroughly cleaned to remove any externally 

 adherent arsenic, their bodies are found to contain no traces of the poieon, whilst Ticks similarly removed on each of the six days following dipping; ore 

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



With regard to theory No. 2, it is highly improbable that the arsenic is absorbed through the skin of the Tick, for the fluid dries on tfie skin in less 

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



There only remains then theory No. 3. viz., 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 field goes to support this theory. 



Given dips v\'hich contain equal amounts of the poisonous agent, it hu been proved by actaal experimeot that those wliich spread over and thoroughly 

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

 and uniform penetration over the whole skin surface of the animal. 



ll is a proven fact that (hose dips which saturate the skin in patcha kill only At Ticks whidl MSiera to those patches, ft is found, moreover, tl-,al if 

 a solution ol arsenic is injected subcutaneously, the Ticks attached aroood the tits of the injection are poisoned, and although they have had no contact 

 with arsenic from ih: exterior, tlieir remains are found to contain appreciable quantitie*. This poisonous action is limited to an urea of about 6 inches radiui 

 from the site of inoculation. 



Invesligaiions have shown that arsenic applied to the nndamaged tldo of an annaal does not appear in appreciable 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 

 surface to the interior. The accumulated facts which have resulted from enquiries into the matter lend the greatest support to the theory that the living 

 tells, which form the deeper layers of the skin, have an actual afnnity for arsenic, and the poison is arrested and fixed in them and thus pfevcnled 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 is then easy to suppose that while feeding on a beast which has been recently 

 dipped or sprayed, the lick takes in con::iJ('rable quantities of the poison with the blood and lymph which have necessarily passed through these deeper 

 layers of the skin, which are mere or less saturated with arsenic 



(. COOPER'S CATTLE TICK DIP WEST INDIAN AGENTS ; 



£,- ■ J .1 tf ■ t t r al t ti ■ r- ._■... ANTIOl) A : Bennett, Bryson & Co., St. John*. 



HoM received the official approval of the following Countnet: BAHA.MAS: H. T. Brice. Nassau, N.P. 



„ , BARBADOS: B;irliadn5 Co-operative Cotton Co.. BfldretewB- 



Onlon o( South Africa. Northern Rhodesia. Brazil. Basutoland. BRITISH OUIANA: T. Oeddes Qrant. Ltd. 



Nvasaland. Swaziland. Southern Rhodesia. Madaeawiar. DOMINICA; Hon. M. A. Prnmnton. ORIiNADA : Thom.ion, Hankey * C«. 



OUAlJIiLOUI'l; : The Station Aitronomiguc de la Ouadeloupo, 



British East Africa. Oerman East Africa. Portuguese East Africa. Polnt-^-Pilre. .lAMAICA: D. Henderson & Co., Klncstoo. 



f^uguco west Africa. Eg.pt. Argentine RepubUc. Qu«,nsla„i „0NT.rBR"«AT:'*'>t^.'.:,e^vern Wa* .'°'Nev7sr S^^ 



United States of America. New South Wales. 5T. KITIS : S. L. Hor.sford & Co. ST. LUCIA : Barnard Sons » C%^ 



' „_^. _ _,. . . . „ Castries. ST. VINCENT: Cores & Co.. Klnrstown. 



Northern Territory of AustraUa. TRINIDAD & TOBAOO: T. Oeddes Grant, Ltd, 



AMERICAN VIROIN ISLANDS: O. H. Schmleeelow, St. Creta. 



ilanufacturers : WILLIAM COOPER & NEPHEWS, Berkhamsted, England. 



»&ANCHES : TorMts, aicsfo. Sydacy, MclkMW, iKkkaJ, Bosmm Aires, ModU Vidse, Paala Anaaa, MaaocsWt. (Mmm, 



