TUBERCULOSIS IN ANIMALS 295 



simulate malignant growths and they have been mistaken for neoplasms. 

 Sometimes however they resemble the lesions found in man and this is especi- 

 ally true in cases where cavitation of the lungs has been produced. 



Pigs. Of pigs killed in public slaughter houses [in France] one to ten per 

 thousand are infected with tuberculosis. 



As a general rule, the alimentary tract is the part affected. Tuberculous 

 otitis has been recorded in pigs : when it occurs it is probably secondary to 

 some pharyngeal lesion which has spread up the Eustachian tube. Tuber- 

 culosis of the respiratory passages and localized tuberculous foci are not 

 often seen. The disease is sometimes of a miliary type and runs a rapid 

 course. 



v - 



u, 



FIG. 188. Section of the liver of a pig which died 47 days after intra-venous 

 inoculation with 50 mg. of culture of avian tubercle bacilli. This area is typical 

 of the condition found in the liver of this animal. Note (1) the profuse 

 growth of bacilli, with tendency to rosette formation ; (2) the huge " giant 

 cell " showing multiplication of nuclei by irregular longitudinal splitting ; 

 (3) the absence of wandering cells, with the exception of a few small lympho- 

 cytes ; (4) the presence of numerous bacilli in the blood stream, x 600. 

 (Eastwood.) i 



[The nature of the tubercle bacilli occurring in fifty-nine cases of natural 

 tuberculosis in swine was investigated by A. S. Griffith and F. Griffith (for 

 the English Commission). Of these, fifty (including thirty- three cases of 

 generalized tuberculosis) were shown to be due to the bovine tubercle bacillus ; 

 three (in which the disease was localized in the sub -maxillary glands) were 

 caused by the human tubercle bacillus ; five (in which the disease was similarly 

 localized) by the avian tubercle bacillus ; and from one (localized tubercu- 

 losis) a mixed culture of avian and bovine tubercle bacilli was obtained. 



[Severe and generalized tuberculosis in the pig therefore was by this 

 investigation shown to be due to the bovine tubercle bacillus only.] 



Rabbits. There is no foundation in fact for the popular belief that rabbits 

 are very commonly tuberculous. Spontaneous tuberculosis in the rabbit is, 

 on the contrary, a comparatively rare disease. When it occurs it assumes 

 the pulmonary form. 



Goats and sheep. Both goats and sheep are liable to infection with tuber- 

 culosis but the disease in these animals is uncommon. 



['This figure as well as figures 191, 192, 193, 198, 199, 200, 201, 202, 203, 205 and 206 

 are from the Final Report of the Royal Commission on Tuberculosis (Human and 

 Bovine) Part II. Appendix, Vol. V. ; Dr. Arthur Eastwood by permission of the Con- 

 troller of H.M. Stationery Office.] 



