352 - Multicellular Animals, Especially Man 



movement in one hour, after the vitamin is 

 injected intravenously (Fig. 18-4). Drastic 

 beriberi became prevalent for a time among 

 rice-eating populations when modern meth- 

 ods of polishing the grain began to be 

 adopted. The outer seed coats of the cereal 

 grains arc excellent sources of thiamine and 

 the other vitamins of the B-complex. and 

 consequently highly refined grain is a poor 

 substitute for whole grain (Table 18-3). 



A deficiency of vitamin B., (riboflavin) 

 leads to various symptoms, including (1) loss 

 of weight; (2) a scaliness of the skin around 

 the mouth and cars; and (3) a predisposition 

 to cataract (Fig. 18-5). Riboflavin, thiamine, 

 niacin, pyridoxin, and cobalamin (see Table 

 18-3) all serve as coenzymes in various reac- 

 tions in cellular metabolism (p. 104). 



Pellagra is still a fairly prevalent deficiency 

 disease. This is especially true in some dis- 

 tricts of the South Atlantic states, where the 

 traditional diet is restricted mainly to maize, 

 molasses, and meat. The main symptoms of 

 pellagra are dermatitis and diarrhea, al- 

 though severe pellagra may terminate finally 

 in prostration and death. The main pellagra- 

 preventing (P-P) factor is niacin, which also 

 has been called nicotinic acid, although many 

 cases of pellagra ate complicated by an ab- 

 sence of other B-complex vitamins. Niacin 

 has become available — since the vitamin has 

 been isolated and synthesized artificially— 

 but traditions of diets are hard to eradicate, 

 and pellagra still remains somewhat of a 

 problem. Vitamin B fi (pyridoxin) — the anti- 

 dermatitis factor — is frequently absent from 



Fig. 18-5. Upper photo- 

 graph: Deficency of ribo- 

 flavin retards growth and 

 induces certain changes in 

 the skin. Lower phofograpri: 

 Same animal, restored to 

 normal by riboflavin feeding. 



