BY T. HARVEY JOHNSTON AND M. J. BANCROFT. 231 



Teason to assume that the latter would never be affected 

 at any time or under any circumstances." 



Tryon* mentioned that a large cattle tick, probably 



Amblyornma sp., was reported as killing cattle in North 

 Queensland, even when very few of them were present on 

 the animals. 



It is known that an antieoagulin occurs in certain 

 ticks. Sabbatinif in 1898 isolated' such a substance from 



Ixodes ricinus and found that certain symptoms followed 

 its injection into various animals, dogs being especially 

 susceptible, cats less so, while sheep and cattle were relatively 

 resistant. Nuttall and StricklandJ referred to the presence 

 of an antieoagulin in the salivary glands and intestine of 



Argas and Orniihodorus. 



Christophers** reported that the coxal secretion of 

 Ornithodorus savignyi possessed anticoagulative properties. 

 Kunssbergft found that the antieoagulin was produced by 

 certain gland cells in the salivary glands of Ixodes and 

 Ornithodorus. Cornwall and Patton JJ followed up 

 Sabbatini's work and asked the question as to whether the 

 salivary antieoagulin was the substance which caused the 

 irritation following the bite of a blood-sucking arthropod. 

 We have carried out a series of experiments with 

 Boophilus australis along the lines of those published by 

 Nuttall and Strickland, and have found that an antieoagulin 

 exists in the salivary and Gene's gland but that its action 

 on human blood is much less pronounced than that of 



Argas. This is to be expected, owing to the difference 

 in the feedinjr habits of the two ticks. 



*Tiyon, Ann. Rep. Dept. Agr. Q'land, 1915-G (1916), p. 50. 



jSabbatini, Fermento anticoagul?.,nte dell Ixodes ricinns. Arch. 

 Ital. biol. Turin, 31, 1899^ — abstract in Nuttall and Strickland. Parasitol. 

 I, 1908, pp. 303-4 — also referred to by Cornwall and Patton, 1914. 



JNuttall and Strickland, I.e., 1908, pp. 302-310. 



"""Christophers, S. Anatomy and histology of ticks. 8ci. Memoirs 

 -Mod. San. Dei.t.. India, No. 23, 1906, p. 45. 



ttKunsslw.'g, K. Eine AnticoaguHndruso boi Zeckon, Zool. Anz., 

 38, 1911, pp. 263-8. 



f JComwall, J. and I'atton, W. S. Some observations on the salivary 

 secretion of the commoner blood-sucking insects and ticks. Ind. Jour. 

 _Med. Research, 2 (2), 1914, pp. 569-593. (Argas, p. 583-4). 



