230 A TICK-RESISTANT CONDITION IN CATTLE. 



its effects, paralysis and death being usual. Other animals 

 are attacked, sometimes fatally, e.g., cats, pigs, horses 

 and cattle (especially while young), and even ducks.* 



Having in mind certain resemblances between the 

 effects produced in dogs by this tick and those caused by 

 the fowl tick Argus persicus ( A. americana) in domestic 

 poultry through the introduction of Spirochceta gallinarum 

 which causes fowl tick fever. Dr. Cleland and the senior 

 author (while in Sydney in 1910) carefully examined blood 

 from affected dogs, but failed to detect the presence 

 of any spirochsetes. Considerable experimental work 

 relating to this tick was carried out by T. L. Bancroft. f 

 The effects are almost certainly due to the injection 

 of some poison. Immunity commonly follows recovery 

 from bites. Mr. W. Davidson has kindly forwarded 

 information (16th October, 1918), relating to the establish- 

 ment of such a condition in dogs in his district (Tambourine 

 Mountain) : "So far as I have observed with regard to dogs 

 and scrub ticks after an experience up here of over 23 

 years, it appears that if you extract the first scrub tick from 

 a dog before it has been fixed more than about 24 hours, 

 no bad results follow ; if later you extract the second tick 

 that becomes fixed, before it has been in, say, 48 hours no 

 bad residts follow ; and if on the third occasion you extract 

 the tick just as it begins to assume a rather greyish swollen 

 abdomen (the first signs of incipient engorgement) no 

 harmful results are produced, and you may safely assume 

 that your dog is immune. If you have a valuable dog this 

 is by far the best method to adopt to protect him, but it 

 means looking over him carefully every day. . . • 

 Wild animals appear to be immune to the attacks of scrub 

 ticks, e.g., dingoes, iguanas and carpet snakes are generally 

 more or less infested and never seem to suffer. I have 



*T. L. Bancroft, Queenslandar, 3id Jan. 1891, Brit. Med. Jour., 16th 



May, 1191 also quoted in Neumann, Parasites, etc., of 



domesticated animals (Engl, transl. by Fleming), 1892, pp. 103-4. . . . ; 

 H. Tryon, in Ann. Reports Dept. Agr. Q'land, 1911 (p. 80, fatal to 

 calves); 1917 (p. 54, fatal to ducks); etc.; R.S.C., 1911, evidence by 

 Pound (p, 23, dogs and fowls) ; and by Ramm (p. 2, foals, pigs, dogs, etc. J 

 -49, man, etc.) ; Editorial, Cure for tick poison, Q.A.J., 22, 1909, p. 105-6. 



tT. L. Bancroft, I.e. 



