BY T. HARVEY JOHNSTON AND M. J. BANCROFT. 299 



animals so treated six became resistant, the peculiarity 

 ■developing about six weeks later. 



Mr. Inigo Jones, Crohamhurst, practises vaccination, 

 his method being described elsewhere. He has found that 

 some animals will not '" take "' but that the treatment is 

 usually efficacious. 



Mr. R. Cross, Graceville, is another adherent to the 

 vaccination theory {see statement already given). 



Pound reported against such mode of transmission 

 <1914, 1916), as also did Thorn (R.S.C., p. 29). One of us 

 •endeavoured to '" vaccinate," using " exudate " sent down 

 to Brisbane by Mr. Hull on various occasions. The sub- 

 stance when sent dry was pounded up with glycerine or <;lse 

 "' extracted " with glycerine and after carefully cleansing 

 the skin with alcohol, was placed in cuts made on the hind 

 quarters of animals. 



In January and March, 1917, owing to the kindness of 

 Mr. D. A. Rooke, we were enabled to test the effect on a 

 number of his cows at Caloundra. Three ticky animals 

 were "inoculated" on the former occasion. One of these, 

 together with four cows and a ])idl, Avas inoculated in March. 

 No alteration in the degree of infestation has been observed 

 to date, those which wei'e vaccinated being neither more 

 nor less infested than the rest of the herd. 



A small herd of Jersej' and Shorthorn crossbreds in 

 Brisbane was also utilised (November, 1915-June, 1917). 

 One M^as " vaccinated " once, and two twice, but there was 

 no appearance of an exudation up to the time that they 

 were disposed of (June, 1917). Though attempts were 

 made to infest these with larvae artificially and though some 

 ticks were present in the paddock, they remained practically 

 free, as did also the three control cows. These animals, 

 which are now the property of Mr. Jacobson, Mooloolah, 

 were examined in March last. Five of them which were 

 running with dry stock, were all very lightly infested, while 

 another was perfectly clean though its companions in the 

 milking herd were quite ticky. The last named was 

 one of our control animals, while three of the former group 

 had been " vaccinated." The results of our experiments, 

 then, are negative. 



