THE AGRICULTURAL NEWS. 



How Ticks are Killed 



When Cattle 

 Are Dipped or Sprayed 



i 



CATILt TICK 



A knowledge of how a clip is absorbed by, Ticks when callle are dipped or sprayed wilh an arsenical wash is of great assistance in elm 

 problem o( Tick destruclion. Although ibis Mir jecl has given rue to much conjecture, very little definite information is ob a result of i 



experiment. Work directed by William Cooper and Nephews in South Africa has, however, furnished results from which feasible deductions haie been 

 made, and lh tppea ''<■■' ' ht on (fu ! bjeel 



The theories advanced by d.ifcrcnt workers are : — 



1. Tint the Tick absorbs the poison through its own skin duri iocess of dipping or spraying. 



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



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

 the animal. 



It follov, from No. 1 theory, and it is asserted by those who favour this theory, that the longer the period of immersion of the animal in the tick! 

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



• As a 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 wash, and are thoroughly cleaned to remove any ex:- 

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

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



Wilh 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 the skin ii 

 than 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, 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 wilh dips in the field goes to support this theory. 



Given dips which contain equal amounts of the poisonous agent, it has been proved by actual experiment 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 surface of the animal. 



Il i' a proven fact that those dips which saturate the skin in patches kill only the Ticks which adhere to those patches. It is found, moreover, that if 

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

 with arsenic from the exterior, their remains are found to contain appreciable quantities. 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 appreciable quantities in the internal organs of 

 the body. 1 his 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 

 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 

 wilh 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 tick takes in considerable quantities of the poison with the blood and lymph which have necessarily passed through these deeper 

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



COOPER'S CATTLE TICK DIP WEST INDIAN AGENTS : 



Has receive* the official approval of the follou,in g Countries: «. K.TT5 : ^H.rslord ^-^ ANTMC^ : Be^U. Bry^n * C.. 



Union of South Africa, Northern Rhodesia. Brazil. Basu.oland, ^^^^"^^Co.. Ltd. 



Nyasaland, Swaziland, Southern Rhodesia. Madagascar, TRINIDAD: T. deddaa Grant. Port ol Spain. 



British East Africn, C.erman Fast Africa. Portuguese East Africa, BRITISH OUUNA: Sandbach, Parker & Co. 



.. „ «.■■. n - . i ST. VINCENT: Corea & Co.. kinicslown. NBVIS: s. I). Malone. 



Portuguese West Mrica, Egypt, Argentine Republic, Oueensland, danism west indies: Cnri v. i a licet. St. Thomas. 



^United States of America, Northern Territory of Australia. MONTSERRAT: W. Llewellyn Wall. DOMINICA: Hon. H. A. Framnton 



Manufacturers : WILLIAM COOPER & NEPHEWS, Berkhamsted, England. 



BRANCHES : Toronto, Chicago, Sydney, Melbourne, Auckland, Buenos Aires, Monte Video, Punta Arenas, East London, Odessa. 



