234 SECRETS OF EARTH AND SEA 



vegetables and from some foods of animal origin. These 

 " vitamines " are destroyed by heat and by desiccation. 

 They have not yet been isolated though in some cases 

 extracted in a nearly pure state. Their presence or 

 absence is demonstrated by careful experiments in feeding 

 animals, such as guinea-pigs, with weighed quantities of 

 different foods. The "vitamine" is often found to be 

 present only in one part of a seed or fruit or special kind 

 of fat liable to be rejected in food preparation. An 

 important fact is that it may not amount to as much as 

 one-ten-thousandth of the weight of the food in which 

 it occurs ; and the part containing it may be overlooked 

 and rejected, or its value destroyed by heat or by desic- 

 cation. A committee on these "accessory food-factors" 

 is carrying on experiments at the Lister Institute. Dr. 

 F. G. Hopkins, F.R.S., who first discovered the importance 

 of one of these factors in feeding young rats, is the chair- 

 man, and Dr. Harriette Chick is the secretary. Three 

 kinds of these vitamines, or accessory food-factors, have 

 up to this date been recognized. The first is the anti- 

 neuritic or anti-beri-beri vitamine. Its principal sources 

 are the seeds of plants and the eggs of animals — yeast- 

 cells are a rich source of it. Where "polished rice," as 

 in the Far East, is the staple article of diet, to the almost 

 entire exclusion of other food-stuffs, lassitude and severe 

 pains like those of rheumatism set in, and a whole colony 

 or shipload of Chinese " coolies " may be disabled. The 

 disease is called beri-beri, and it can be cured by ad- 

 ministering that part of the rice-grain (the skin and germ) 

 which is removed by " polishing," and unfortunately is 

 just that part which contains the needful vitamine. It 

 exists in very minute quantity, amounting to only one 

 part in ten thousand by weight of rice-grain. The second 

 " vitamine " recognized is the anti-rachitic factor (studied 

 by Hopkins), which tends to promote growth and prevent 



