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. Gr 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 



