J. B. Cleland 
219 
tumours has a definite etiological relation to their formation or is 
only an accidental denizen of their cavity, introduced at the time of 
castration with the organism causing the swelling, it is impossible to 
say. 
Recently Sydney Dodd, in the Journal of Comparative Pathology 
vol. xix. 1906 (vide note, Journal of Tropical Vet. Science, vol. n. 
no. 2), has described an ulcerative skin disease of pigs, in which the 
ulcers contained spirochaetes apparently somewhat similar to these. 
