MICROBIAL DISEASES OF MAN AND DOMESTIC ANIMALS 813 



the meningeal meinbranes. This disease is supposed to be transmitted 

 by ticks, not the wingless fly which is generally called a "sheep tick" 

 in the United States, but true ticks, belonging to the genus Ixodes. 

 The specific microorganism has not been discovered. 



Pellagra* 



Pellagra is a disease of man characterized by the annually recurring 

 manifestation, each spring or summer, of erythema on the backs of 

 the hands and forearms and sometimes on the face and neck, feet and 

 ankles, coupled with digestive disorder and more or less well-marked 

 mental disturbances. During the winter the signs of the disease usually 

 disappear. " 



At present there are two main groups of theories concerning the 

 causation of pellagra, each of which includes a multitude of hypotheses. 

 According to one group of theories pellagra is a food poisoning due to 

 eating maize (Indian corn) ; according to the other, pellagra is a specific 

 infectious disease not necessarily associated with the ingestion of corn. 

 None of the theories concerning causation is supported by conclusive 

 evidence. The evidence against the corn theory marshalled by Sambonf 

 and others t has greatly weakened the almost general belief in this 

 theory which formerly obtained. Some prominent zeists § have recently 

 shown a tendency to ascribe pellagra not essentially to the use of maize 

 but to a supposed deficiency or lack of a necessary something in the 

 diet. This change of opinion has been caused in part by the failure 

 of the maize theory when put to the test of actual observation and in 

 part by an eager application to pellagra of the facts learned in the 

 study of another disease, namely, beriberi. To the writer it seems 

 very improbable that this new phase of the dietary theory will survive 

 as long as has the maize theory proper, although it has recently received 

 enthusiastic support from the U. S. Public Health Service. || 



* Prepared by W. J. MacNeaL 



t Sambon, Brit. Med. Journ., Nov. 11, 190s; Joum. Trop. Med. and Hyg., 1910, Vol. XIII 

 271-282; 287-30OJ 305-315; 319-321- 



X Siler and Garrison, Amer. Journ. Med. Sciences, July, I9i3i Vol. CXLVI, p. 42; ibid., Aug., 

 1913, Vol. CXLVI, p. 238; Siler, Garrison and MacNeal, Joum. A.M.A., 1914, Vol. LXII, 

 pp. 8-12. 



§ Sandwith, Trans. Soc. Trop. Med. and Hyg., 1913. VI, p.p. 143-148; Weiss, Riv. 

 Pellagrologica Italiana, 1913. XIII, 90; DriscoU, Southern Med. Journ., 1913, VI, pp. 400-401. 



II Goldberger, Joseph, and collaborators. Public Health Rep., June 26, 1914, Vol. XXIX, 

 p.[i683; ibid., Sep. 11, 1914, Vol. XXIX, p. 2354; ibid,, Oct. 22, 1915, Vol. XXX, p. 3117; ibid., 

 Nov. 12, 191S, Vol. XXX, p. 3336. 



