BY T. HARVEY JOHNSTON AND M. J. BANCROFT. 301 



Our experiments in regard to " vaccination " and 

 ■" contact ' ' have given much the same result as that reported 

 by Messrs. Pound and Thorn. We would like to point out 

 liowever, that we used only glycerinated material. Perhaps 

 the employment of fresh exudate may have led to more 

 •satisfactory results. 



In this connection Ave would like to emphasise our 

 remarks made earlier in this paper (see under section " Tick 

 poison ") when dealing Avith the ({uestion of tick poison, 

 the production of anti-tick bodies and the possibility of 

 using an animal with blood rich in such substances, as a 

 ^' bleeder " for supplying material for inoculation in order 

 to obtain passive immunity. 



Mr. Hull forwarded the following account (19th 

 February, 1916), of his experiments in regard to trans- 

 mission by " vaccination " and '" contact." 



I. Blood from Clover inoculated into three cows and 

 three calves. 



Result : — One cow re-acted for piroplasmosis. The 

 three cows remained liable to ordinary' tick infestation 

 until dis]iosed of. Calves exhibited no abnormal conditions 

 until disposed of at two years old. 



II. Exudate from "tick sores" on Clover vaccinated 

 into nine young cows obtained from different districts. 



Result : — Five re-acted by exhibiting a serous exudate 

 on escutcheon, close to vulva, and developed resistance, 

 requiring no treatment as regards ticks. Close observation 

 revealed presence of abundant dead larvae and occasional 

 fully -engorged females, the latter increasing in number in 

 the winter months. This condition was maintained until 

 ■cattle were disposed of several years later. 



III. Inoculation by exudate from "tick sores" on 

 ■Clover into five young cows. 



Result : — Three re-acted and maintained similar con- 

 ditions as in Experiment II. 



IV. Contact experiment. Ten young cows from 12- 

 15 months old obtained from Rosewood — inoculated with- 

 out loss by A. E. Cook, of Eumundi, against piroplasmosis. 



