DISEASES AND PARASITES OF MAMMALS QI 



numerous as to consume the entire food supply and thus possibly 

 become exterminated through starvation. The varying hare in Alberta 

 is said to thus limit its own increase by epidemics about every seven 

 years, at the period of maximum abundance. The same sort of thing 

 happens in case of voles and lemmings, whose periods of unusual 

 abundance are usually ended by epidemics. 11 Such epidemics, affecting 

 only injurious mammals, are of distinct benefit to the human race. 



Among diseases of rabbits in captivity are mentioned mange, slob- 

 bers, snuffles, sore eyes, sore hocks, vent disease, ear canker, and 

 warbles. 12 Tularemia is discussed at some length in the next chapter. 

 In many wild rabbits are found cysts, 13 which injure the meat for food 

 purposes. Some squirrels are infested with scabies. 14 A wildcat in cap- 

 tivity was infested with intestinal, muscular and pulmonary parasites, 

 and a white rhinoceros was infested with round worms. 15 Foxes on 

 fox farms are subject to a number of diseases, such as mange, diar- 

 rhoea, constipation, worms, indigestion, tuberculosis, kidney disease, 

 intestinal abscesses, 16 "fox paratyphoid" and "epizootic fox encepha- 

 litis." 17 The best-conducted fox farms have hospital wards or pens for 

 the occupancy of the sick foxes. 18 The western dog-tick infests not only 

 dogs, but also sheep, cattle, horses, ground squirrels, and one dead deer 

 was found to be covered with them. 19 One case of diseased tonsils in the 

 wolf 20 is reported, and tuberculosis in marsupials. 21 



Various members of the deer family are subject to the foot-and- 



11 Henderson, A. D., Cycles of abundance and scarcity in certain mammals and 

 birds, Journ. Mammalogy, iv, 264-265, 1923. Innis, The Canada fur trade, p. 90, 1927. 

 Howell, Periodic fluctuations in the numbers of small mammals, Journ. Mammalogy, 

 iv, 149-155, 1923. Elton, Periodic fluctuations in the number of animals: Their causes 

 and effects, British Journ. Exper. BioL, 11, 1924 (quoted by Innis) ; Plague and the 

 regulation of numbers of wild animals, Journ. Hygiene, xxiv, 138-163, 1925. Soper, 

 Notes on the snowshoe rabbit, Journ. Mammalogy, u, 101-107, 1921. 



"Dearborn, Rabbit raising, U. S. Dept. Agric., Farmers' Bull, No. 1090, pp. 

 32-34, 1920. DeOng, Parasites which affect the food value of rabbits, California Fish 

 and Game, i, 142-143, 1914. Schwartz and Snook, Rabbit parasites and diseases, 

 Farmer's Bull. No. 1568, 1928. Marine, The cure and prevention of ear canker in 

 rabbits, Science, LX, 158, 1924; see also same volume, pp. 429-430. 



13 See, for example, Crawley, Proc. Acad. Nat. Sci. Phila., LXVI, 214-218, 432-436, 

 1914. 



" Bryant, Tree squirrels infested with scabies, California Fish and Game, vn, 128, 

 1921. Shannon, Gray squirrel disease spreading, Californa Fish and Game, vni, 52, 

 1922. 



13 Fox, Disease in captive mammals and birds, p. 3, 1923. 



18 Jones, Fur farming in Canada, pp. 41, 43, 45, 67, 1913. 



17 Fox distemper being investigated, California Fish and Game, xiv, 232-233, 

 1928. 



18 Ashbrook, Fur farming for Profit, pp. 62-65, 1928. 



"Wright, Yosemite Nature Notes, vn, No. 5, p. 38; California Fish and Game, 

 xiv, 252-253, 1928. 



20 Scott, Carcinoma of the tonsils in the common wolf (Canis lupus), Proc. Zool. 

 Soc. London, 1928, Part i, pp. 43-47. 



21 Scott, Tuberculosis in marsupials, Proc. Zool. Soc. London, 1928, pp. 249-256. 



