PHYSIOLOGICAL 279 



utilisation of fat in the body and with resistance to infectious 

 diseases. 



(B) Water-soluble vitamin B is found in cereals, pulses, eggs, 

 yeast ("marmite"), lemons, and the like. It counteracts beri-beri 

 disease and works against certain forms of nervous breaking-down. 

 It is technically called "anti-neuritic". It is now generally regarded 

 as a complex of several vitamins. 



(C) Vitamin C, which works against scurvy, is abundant in 

 green vegetable like cress, in fresh fruits like lemons, and especially 

 in sprouting seeds. It is technically called anti-scorbutic. 



(D) Allied to fat-soluble vitamin A is another with similar 

 physical properties and distribution, which works against imper- 

 fect bone-forming in children, in other words against "rickets". 

 It is therefore technically called anti-rachitic. But its work in 

 promoting the proper use of lime-salts in bone-making has to be 

 backed up by plenty of sunlight. 



(E) Of great interest, but clouded in uncertainty, is a new fat- 

 soluble vitamin E, abundant in ether-extract of wheat embryos, 

 and in dried leaves of lettuce. It occurs unhurt in dried leaves of 

 peas, in seeds like cotton and Indian corn, in some fruits like 

 bananas, in yolk of egg, and in many animal tissues. Experiments 

 with rats indicate that this vitamin is necessary for the successful 

 development and birth of offspring. Perhaps the biggest fact in 

 regard to all these vitamins is simply that they are abundantly 

 present in mixed natural food, not too much cooked, and not made 

 over-dainty. 



Vitamins and Light. — It is now a widely-known fact that an 

 adequate diet must contain not merely sufficient proteins, fats 

 and carbohydrates to furnish energy and maintain the tissues of 

 the body, but also, as above noted, certain "accessory food- 

 factors" or "vitamins" essential to health. For example, an artificial 

 milk can be made up, containing the same proteins, fats and carbo- 

 hydrates as natural milk; but animals fed on such a synthetic diet 

 cease to grow, develop various definite disorders, and presently 

 die, in the absence of the vitamins which natural milks, and many 

 other natural foods, contain. Inadequate supplies of certain of 

 these vitamins lead, in man, to disorders like beri-beri and scurvy. 

 Many natural fats (butter, cod-liver oil) contain vitamins in whose 

 total or partial absence young animals cease to grow, fail to form 

 bones correctly (rickets), and become subject to disorders of the 

 breathing-passages on the one hand and of the eye (xerophthalmia) 

 on the other. It is probable that at least two factors are missing 

 or deficient in such cases; their chemical nature, it must be said, 

 is quite unknown. It is found that exposure to sunlight helps 

 animals, such as rats, to ward off the eye disorders due to a 

 deficiency of "vitamin A" in the diet. Ultra-violet light, which, 



