ETIOLOGY 



1711 



work on this basis has been so far a failure, for, although the disease 

 has diminished in certain regions for a time, it has later returned 

 with considerable vigour. With regard to the presence of pellagra 

 in Europe before the introduction of maize there is no trustw^orthy 

 evidence, and the possible occurrence of the disease in the celebrated 

 St. Francis of Assisi is only an interesting speculation. 



After carefully considering all the facts in support of the maize 

 theory, and comparing them with those against, we have come to 

 the opinion that the maize theory, in general, is so far based upon 

 insufficient foundations. It is, however, necessary to lay before 

 the reader the various phases of this theory, which may be classified 

 as follows: — 



1. Photodynamic theory. 



2. Deficiency. 



3. Toxicity. 



4. Infectivity. 



I. Photodynamic Theory. — The special promoter of this theory is 

 Raubitschek, whose work has tended to show that an exclusive 

 maize diet, good or bad, proves deleterious to white mice and guinea- 

 pigs if these animals are exposed to sunlight. He also suggests that 

 an exclusive diet of other cereals, such as rice, millet, or wheat, 

 might, under similar circumstances, produce the same phenomena. 

 This theory maintains that photodynamic substances are introduced 

 by the cereals into the blood, and these, under the influence of sun- 

 light, become toxins, and thus cause inflammation of the skin 

 and other symptoms resembhng to some extent pellagra. More- 

 over, Raubitschek maintains that he has cured mice suffering from 

 fagopyrism by keeping them in darkness, even though the diet was 

 unaltered, and, further, that he has obtained favourable results 

 by excluding light from the skin of pellagrins by means of darkened 

 rooms, red windows, ointments, bandages, etc. Hirschfelder has 

 searched for this fluorescent (photodynamic) substance in the 

 blood serum of five patients suffering from severe pellagra, and 

 found that there was no difference in the fluorescence between 

 their serum and that of healthy persons. Moreover, fagopyrism 

 only occurs in white animals, and not in black; whereas pellagra 

 can occur in the jet black negro, which appears to us to be a strong 

 objection. 



2. Deficiency. — This theory has been mentioned above with regard 

 to the absence of nitrogenous complexes, and it only remains to 

 add that protein deficiency has also been brought forward as a 

 possible explanation of the action of maize in producing pellagra, 

 but has no sound foundation. Moreover, many people live on rice 

 and potato, which have lower nitrogen ratios than maize. 



3. Toxicity. — Volpino, Mariani, Bordoni, and Alpago-Novello, 

 have made investigations with regard to inoculating maize ex- 

 tracts into patients, obtaining several general reactions. These 

 experiments support the latest view, which is really only the revival 



