PELLAGRA 331 



Other cereals do the same. It is maintained that photo- 

 dynamic substances are introduced by cereals into the 

 blood. These with sunlight produce toxins and cause 

 pellagra symptoms. In darkness mice have been cured. 

 Cox. Hirschfelder searched the blood of severe cases for the 

 photodynamic substance, but failed to find any. 

 Pellagra occurs in jet-black negroes, whose pigment protects 

 them consjderablv from the sun's rays. 



The Deficiency Theory. 

 Pro. Insufficient protein in maize food. 



Con. Many live on rice and potatoes which contain less nitrogen 

 ratio than maize. 



The Toxicity Theory. 



Some claim that there is an — 



Individual susceptibility to maize intoxication. 



Others that there are toxins produced in the spring bv the germina- 

 tion of maize. 



Others that there are toxins generated in the bowel by aid of the 

 B. coli. 



Others that there are alkaloidal and other poisons in fermenting 

 maize. 



The Infectivity Theory. 



The most popular view. The maize is cultivated and harvested 

 under unfa\ ourable conditions, and stored in damp places and be- 

 comes mouldy. Ilirsch states that after a bad season cases increase. 

 This infection may be : — 



(i) Func^i as Pernicious glaucum, Aspergillus, &c., the fungi 



or their toxins. 

 (2) Bacteria as B. solanacearum, B. subtilis, B. pellagr^e. 



(3) The Parasitic Theory. 



This is supported by the Illinois Commission. 



A. Vegetable Parasite, e.g., Tizzoni's streptobacillus. 



He claims to have found it in the blood, cerebrospinal fluid, 

 and viscera of pellagrins after death. Others refute this. 



B. Animal Parasites. 



(i) A slender nematode worm (Filaridae alessandrina) in drinking 

 water. 



(2) A phase of ama?bic dysentery (Long). 



(3) A protozoan infection spread by a biting fly (Sambon). 



