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Scientific Proceedings (131) 



fat-soluble A is the cause of rickets. This assumption was soon 

 proved to be erroneous, and a second natural assumption was 

 made by McCollum that the deficiency of another vitamin was 

 responsible for rickets production. No one doubts the existence 

 in cod liver oil of a substance having a favorable influence on 

 mineral metabolism. If this substance is concerned in the rickets 

 of infants then we must be able to show that a normal diet for 

 infants contains the substance in sufficient amount and that when 

 rickets occurs the substance is deficient. It is perfectly well 

 known, however, that rickets occurs quite freely in infants on 

 mother's milk or on best grades of fresh cow's milk. It is, fur- 

 thermore, a well established fact that rachitic infants are not 

 cured by the addition of liberal amounts of cream to their diet. 



Both Park and Howland believe that an anti-rachitic vitamin 

 occurs in foods probably associated with the fat-soluble A in 

 green leaves. Having found a method by which we can mate- 

 rially concentrate the active substance from cod liver oil, we 

 investigated the occurrence of this material in various plant and 

 animal substances. We have subjected the following materials 

 to the processes similar to those by which we obtained a sub- 

 stance from cod liver oil one thousand times as active as cod 

 liver oil itself : butter, cocoanut oil, spinach, carrots, pig's liver 

 and sheep's adrenals. From none of these materials were we 

 able to obtain an extract which even without dilution approached 

 the action of cod liver oil, while from cod liver oil itself we 

 obtained extracts at least one hundred and later more than one 

 thousand times more active than the original cod liver oil. We 

 cannot say that these preparations were entirely free from anti- 

 rachitic substance, but the amounts, if there was any, were so 

 small that they gave minimal and irregular results. Taking as 

 an example the plant materials spinach and carrots — these were 

 treated first with acetone, then with ether, then with alcohol and 

 again ether. We believe that this gave us a thorough extraction 

 of the fats contained in the plant tissues. This fat was then 

 saponified and put through procedures previously described. 

 The extraction of the fats must have concentrated the material 

 at least ten times and the further processes at least one hundred 

 times. On this basis, spinach or carrots if they contain any anti- 

 rachitic material will require four kilogram to furnish as much 

 as one teaspoon ful of cod liver oil. We can safely say then that 



