44 BIOLOGICAL PROBLEMS 



with sleeping sickness, with which it has no possible 

 connection, and there is usually a vague idea in the 

 public mind that it is associated with the eating of 

 polished rice. 



Its symptoms are those of a peripheral neuritis; 

 there is loss of power in the arms and legs, and fre- 

 quently at some stage there is dropsy. The disease 

 is usually accompanied by great wasting, and may 

 suddenly terminate fatally from heart failure. On the 

 post-mortem examination nerve degeneration is found. 



The symptoms of experimental polyneuritis of 

 pigeons are also those of a peripheral neuritis. The 

 birds become lame and unable to fly; there is loss of 

 balance, and the head is held in a peculiar retracted 

 position very characteristic of the disease. There is 

 seldom or never dropsy, but death may occur sud- 

 denly from heart failure, and the post-mortem exami- 

 nation reveals great nerve degeneration. 



Beriberi is most common amongst rice -eating 

 peoples, and among them is almost universally con- 

 fined to those who eat the rice from which the skin or 

 cortex, together with the embryo, germ, or plantlet 

 have been removed. It is not, however, confined to 

 rice-eating peoples; any diet consisting too largely 

 of highly-milled cereals, whether wheat, maize, rice, 

 or any other grain, will equally well produce it. 



Experimental polyneuritis of pigeons is produced 

 in the same way, by feeding decorticated grain ; the 

 ordinary white rice of commerce is ordinarily used, 

 but the disease will as certainly result from a diet 

 consisting exclusively, or for the greater part, of pure 

 white wheat flour. Dr. Chick and I have so produced 

 polyneuritis in pigeons, and cases are on record where 

 beriberi has occurred on such a diet among human 

 beings. An interesting story is extant of an old Nor- 

 wegian ship's captain, which illustrates the point well. 



