NUTRITION AND GROWTH 619 



Investigation of the distribution of the vitamins among the various 

 foodstuffs, and their degree of stability towards heating, etc., has been 

 very materially facilitated by the fact that certain of the lower animals 

 suffer diseases like those seen in man when vitamins are absent from 

 the diet. This renders it possible to prosecute the investigations in- 

 tensively and under scientifically controlled conditions, thus affording 

 knowledge which enables us to alleviate human suffering. 



The Antiberiberi or Antineuritic Vitamin. Beriberi is a disease char- 

 acterized by wasting, anesthesia and paralysis, and sometimes by ex- 

 cessive edema. Pathologically, it is a form of severe neuritis. It is 

 common in rice-eating communities, and the first clue to its chief cause 

 was afforded by the observation that it does not occur among people 

 who take unmilled rice, and that it disappears in those who take "pol- 

 ished" rice when the millings or a watery extract of them (pericarp and 

 germ) are added to the diet. It was observed by Eijkman that the poul- 

 try of a prison where beriberi was prevalent exhibited symptoms very 

 like those of the human disease, and further investigation showed ex- 

 tensive nerve degeneration to exist in the affected animals. Pigeons 

 fed on polished rice develop exactly the same symptoms so that experi- 

 mental investigation soon rendered it possible to determine with accu- 

 racy which foodstuffs prevent beriberi. Meanwhile McCollum and Davis 

 discovered that the absence of the same water-soluble vitamin interfered 

 seriously with the growth of young animals. This is shown in Curve II of 

 Pig. 186, from the observations of Hopkins and Chick, and is con- 

 structed on the same principles as those of Fig. 184. It will be observed 

 that the withdrawal of the vitamin caused an immediate cessation of 

 growth followed by a period during which the body weight remained 

 more or less constant, but ultimately declined. The fact discovered by 

 McCarrison 75 that atrophy of the gastrointestinal tract also results from 

 deficiency in this vitamin, may be responsible in part at least for the 

 failure of growth. During this stage muscular incoordination is a 

 prominent symptom, and death ultimately occurs. The curves show 

 that this vitamin must soon disappear from the organism when it is with- 

 drawn from the food and that the animal cannot synthetize it. 



It will be noted in the table on page 623 that vitamin B is present 

 in abundance in the seeds of plants and the eggs of animals. It is 

 very plentiful in yeast and in yeast extracts, which may therefore 

 be added to the diet when there is risk of its deficiency. It is ab- 

 sent from bread made with white wheat flour, but beriberi is rare in 

 people living on this food, since other foodstuffs containing the vitamin 

 are usually also taken. Beriberi is unknown where rye bread is the 

 staple food. 



The Antirachitic Vitamin (Fat-Soluble A Factor). The first inkling 



