94 DIGESTION 



process in the green leaf, the process which results in the 

 formation of chlorophyll. Vitamin A at any rate only ap- 

 pears when the plant turns green. Vitamin C, however, 

 appears when the seed germinates and before any green parts 

 of the plant are formed, and Vitamin B exists in large pro- 

 portions in the colourless yeast cells. Possibly the vitamins 

 act as Enzymes (or ferments), pulling the trigger, as it were, 

 to set other food substances at work to build up flesh and 

 renew waste in the animal body. Possibly the same is true 

 also in the bodies of some plants, e.g. Fungi and some Algae. 

 Fat Soluble Vitamin A is found in many animal fats, e.g. in 

 butter, but not in lard; and not in most vegetable oils or fats, 

 though there is some in nuts and nut-butter. Lack of this 

 vitamin may cause rickets in children. The bone does not 

 harden, and growth is either not possible, or is badly stunted. 

 Eggs and milk contain Fat Soluble Vitamin A, and in experi- 

 ments on rats it has been found that rats fed on foods without 

 this vitamin became almost paralyzed and could not move 

 their hind legs, but revived when a little fresh milk or egg 

 was added to their diet. Their eyes, which had become 

 affected and their lids reddened, also became normal again. 

 This Vitamin A is destroyed by oxygen, and this may 

 explain its deficiency in lard, which is often exposed in 

 shallow pans to the air. Margarine, or vegetable fat, does 

 not contain Fat Soluble Vitamin A. Hence the Government 

 Order that margarine (at least during the war) must contain 

 a percentage of animal fat. 



In investigating the causes of scurvy or scorbutic disease 

 at the Lister Institute, it was found that growth in young 

 mammals is also dependent on the presence of the Water 

 Soluble Vitamin B in the diet given, and without the third 

 Water Soluble Vitamin C the skin is not sufficiently nourished 

 and scurvy ensues. 



Water Soluble Vitamin B is found largely in the germ and 

 aleurone-layer below the skin or husk in cereals or grain foods, 

 e.g. in wheat, rice, maize. Two "deficiency" diseases, Beri- 

 Beri and Pellagra, have been traced to the lack of this 

 vitamin. Beri-Beri is largely a tropical disease common, 

 amongst other places, in India, since machine-milling for rice 

 was introduced. This process took away the germ and the 



