NATURAL HISTORY OF THE RABBIT 49 



lest, by feeding on infected rabbits, they finally infect 

 others in their turn. We may appropriately quote 

 here Dr. Cobbold's salutary caution to owners of 

 sporting dogs. ' Sportsmen,' he says, ' who care for 

 the welfare of their dogs should never allow them to 

 devour the entrails of hares captured in the field. In 

 the county of Norfolk I have myself witnessed this 

 piece of carelessness on the part of keepers, and have 

 ventured to remonstrate accordingly. Almost every 

 hare (and the same may be said'of full-grown rabbits) 

 harbours, within its abdominal cavity, a larval parasite 

 {Cannrus pisiformis),vi\ach., when swallowed by the 

 dog, becomes transformed into a tape-worm (Tcenia 

 serrata) varying from two to three feet in length. In 

 harriers and greyhounds this serrated tape-worm is 

 very abundant, but in other dogs it is comparatively 

 rare.' This significant fact should not be lost 

 sight of. 



If we examine a rabbit thus affected we find the 

 hydatid or tumour, sometimes as big as a filbert, sur- 

 rounded by a couple of investing membranes, the 

 outer one belonging to the unfortunate host, the inner 

 one being part of the hydatid itself On opening the 

 body cavity, it will be found to contain amongst the 

 viscera hundreds of the smaller pisiform species of 

 hydatid which, when eaten by dogs, becomes the 



