EK. V. McCollum and N. Simmonds 305 
With the exception of the calcium and magnesium contents the . 
seeds generally resemble each other in most respects in the char- 
acter of their inorganic content. We have described experiments 
which show that each of the more important seeds fails to supply 
an inorganic mixture of a suitable character to support growth 
(3). The similarity in the inorganic content of the seeds would 
suggest that mixtures of seeds should be little better with re- 
spect to this dietary factor than are the seeds when fed singly. 
The experiments reported in this paper demonstrate that this is 
the case. 
In the present series of papers in which we are analyzing by 
biological methods mixtures of foods which are representative 
of the diets employed in those regions where pellagra is preva- 
lent, we are proceeding from the simple to the complex mixtures 
determining in each case the exact nature of the dietary de- 
ficiency. 
The seeds of plants necessarily form a very large part of the 
diet of man, because when ripe they are sufficiently dry to make 
them not difficult to keep in a wholesome condition during a long 
period. Those which are widely employed as food have either 
when raw or develop during cooking flavors which fender them 
acceptable to the palate. This is in marked contrast to the 
leaves of plants which with few exceptions contain tannin or 
other bitter substances which render them unappetizing to man. 
It was never suspected that the seeds as a class had any common 
dietary deficiencies until these were made evident by our system- 
atic feeding of each seed with single and multiple additions of 
the purified food: substances, protein, inorganic salts, and the 
fat-soluble A, in all possible combinations. The biological values 
of the several food factors contained in the most important 
seeds, as revealed by this method, have been discussed at length 
in preceding publications (3). 
The fact that the seeds are not complete from the dietetic stand- 
point has doubtless escaped observation because of the almost 
universal use of fairly liberal amounts of the flesh of animals and 
the products of the dairy in this country and in Europe. Mod- 
erate amounts of milk supplement the deficiencies of the seeds 
most satisfactorily and its use forms the greatest factor of safety 
in our diet. 
