VITAMIN B (B,) 97 



tative comparisons. Now, however, the quahtative survey has (in our 

 opinion) served its purpose and henceforth no investigator should be 

 satisfied with anything less than at least approximately quantitative 

 work. 



The importance of accurate and quantitative measurements in ex- 

 perimental work upon nutrition with special reference to vitamin prob- 

 lems was well emphasized by Chick and Hume who said (1919) : 

 "Since the general conception of accessory food factors (or vitamins) 

 was brought forward, a constant succession of researches has been 

 made to assign values to various foodstuffs as antineuritic, as anti- 

 scorbutic, or as growth-promoting materials respectively, and further 

 to determine whether these values are lessened or destroyed by heat- 

 ing, drying, or other methods of preservation. In most of this work 

 one fundamental consideration — namely that of quantity, has been to 

 a large extent overlooked in the methods adopted for experiment, and 

 the conclusions drawn have been untrustworthy to a corresponding 

 degree. 



"In comparing the values of a series of foodstuffs as regards their 

 value in content of some accessory food factors, it is obvious that the 

 first step necessary is to determine in each case the minimum daily 

 dose which will maintain health in the experimental animal and to 

 institute comparison between these amounts. . . . 



"Similarly, in investigating the effect of heat, drying, or any other 

 method of preservation upon the accessory factors contained in any 

 foodstuff, it is necessary to determine the minimum daily dose (1) of 

 the original untreated material and (2) of the same material after 

 heating, drying, etc., which will protect the same experimental animal 

 under similar conditions of experiment. Then only is it possible to 

 state to what extent, if any, the foodstuff has suffered deterioration 

 as the result of the treatment. 



"Neglect of this simple and fundamental, but admittedly tedious 

 procedure is evident in many papers recently published upon the influ- 

 ence of various treatments upon the antineuritic and antiscorbutic and 

 other properties of certain foodstuffs and the results obtained are in 

 consequence vague, and may even be erroneous. It is clear, for example, 

 that if a foodstuff is rich in any particular accessory factor and is fed 

 to an animal in large excess of the amount actually required, any de- 

 struction of the factor that may take place during heating cannot be 

 assessed and may even remain undetected if the heated material is fed 

 in similar large amount. It is absolutely necessary to determine the 

 minimum required in both cases, and to institute a comparison between 



