236 A TICK-KESISTANT CONDITION IN CATTLE. 



1. These cattle never mature more than a few odd' 

 female cattle ticks during the whole course of a year. 



2. They never require any attention as regards the- 

 tick. 



3. They never need dijjping and may l)e turned out 

 on any country for indefinite periods without suffering 

 any ill effects from cattle ticks. 



4. They are regularly and heavily infested (or attacked) 

 by millions of larval ticks. 



5. With the exceptions mentioned above (No. 1) 

 these infesting ticks die when still very minute. 



6. Probably in the pupa stage {i.e., nymph stage). 



7. The cattle remain at all times sleek and clean in' 

 appearance, without blemish of any description. 



8. That this peculiarity is transmitted in every case 

 to their progeny. 



9. That this peculiarity does not develop in their 

 progeny until after the first year of their life. 



10. That this peculiarity is transmissible by contact^ 

 i.e., b}^ natural infection, and by vaccination. 



11. That the source of infection and vaccination is 

 not a state of dermatitis produced by excessive tick worry, 



12. That the few odd ticks found to mature on these> 

 cattle are not " survivors " but are such as have developed 

 on ordinary cattle, have become displaced without 

 mutilation, and have re-attacked these special cattle. 



13. 14, and 15. Of no importance. 



16. That regular trials, extending without a break for 

 three years, to hatch the eggs laid ])y the few odd mature 

 females found on these cattle have invariably been failures. 



17. That no difficulty was experienced in hatching 

 control eggs from ordinary cattle. 



18. That during the winter months these cattle will 

 mature more female ticks than in summer when ticks are 

 most active. 



19. That temperature tests made in winter with a 

 ground temperature of 53 degrees F., showed that these 

 cattle invariably ranged from one degree to 2^ degrees 

 higher than the ordinary cattle tested at the same time. 



