VITAMINES 231 



year with increasing severity until paralysis and dementia set 

 in, resulting ultimately in death. 



The cause of this disease cannot at present be definitely stated, 

 but there is a certain amount of evidence tending to show that it 

 is due to a deficiency of vitamine. The cereal, maize, constitutes 

 the staple article of diet among the poorer classes in the 

 districts where the disease is most commonly met with, and, 

 as in the case of rice, in the method of preparing the grain for 

 food, the outer layers are often largely removed. These outer 

 layers have been shown by Casimir Funk to be particularly 

 rich in amino compounds, and probably contain an essential 

 vitamine. Feeding animals on polished maize has so far not 

 led to the appearance of symptoms which can be regarded as in 

 any way analogous to those of pellagra, but persons suffering 

 from pellagra may often be cured or greatly benefited by 

 replacing the maize of the diet by other cereals. 



It would seem that maize is not the only cereal which may 

 lead to an outbreak of pellagra. According to a recent report 

 by Dr. Stannus at Zomba in Nyassaland, pellagra is not un- 

 common in the prison at this place and in the surrounding 

 district, although maize is unknown. The diet is, however, 

 very restricted, consisting of rice and salt with little or nothing 

 else. On the other hand, in many regions where maize is the 

 principal foodstuff, pellagra is unknown, which may be ac- 

 counted for by the vitamine theory by the assumption that the 

 necessary vitamine is being supplied from another source, or 

 that the maize used still retains sufficient of its husk to furnish 

 the necessary vitamine. 



An alternative theory, put forward by Sambon, ascribes the 

 disease to a totally different cause, viz. to the action of certain 

 protozoa which are spread through the agency of sand-flies of 

 the genus Simulium. He observed that, at any rate in Italy, 

 the disease was only prevalent in the neighbourhood of swift- 

 flowing streams — the favourite haunts of these flies. The 

 beneficial effect attending removal from such a neighbourhood 

 can therefore be readily understood. 



The chief objections which can be raised against Sambon's 

 theory are that it does not account for the beneficial effects of 

 a change in diet and that it would lead one to expect the 

 disease to be of a more or less infectious nature, which how- 

 ever does not seem to be the case. It has been observed, for 



