E. J. KRAUS 
terials combined with elements from the air. These two classes of materials 
were sometimes spoken of as unelaborated and elaborated foods respectively. 
In general it was stated that if the unelaborated foods predominated, then 
the plant would tend toward the vegetative condition, whereas if the reverse 
were true, reproductive structures would be produced. Somewhat later 
this conception became more concise; nitrogen was considered as being 
the element among the unelaborated materials which was most effective 
in producing the vegeta e condition, and the several types of carbohydrates 
were designated as the significant elaborated foods. Thus, in spite of the 
fact that certain experiments showed the fallacy of the notion, it was 
assumed that whenever leafy, succulent structures were desired, fertilizers 
containing nitrogen would produce the result, but that such fertilizers 
were to be withheld and others rich in potash and phosphorus supplied 
when fruit production was sought. The whole conception carried with it 
the idea that the two functions of vegetative extension and sexual reproduc- 
tion were in some way antagonistic, and statements to that general effect 
may be found widely scattered throughout the literature of both botany 
and horticulture. Such an idea may have arisen from the general observa- 
tion that when the expression of one or the other of these functions is 
reduced the other is apparently increased relative to an assumed average. 
Actually such a condition is generally unreal, for while it may be true that 
certain individual plants in a vigorously vegetative condition may produce 
fewer sexually-reproductive parts, it by no means follows that suppression 
of vegetation in itself will mean increased production of reproductive portions 
or fruitfulness. In fact it is quite possible to suppress reproduction and 
vegetation in direct relation one with another. In other words, it is not 
the mere decrease of vegetativeness that induces the production of parts 
concerned in sexual reproduction, nor the increase of sexual reproduction 
which decreases vegetative extension, but there is an underlying cause 
upon which each rests ; both may be readily increased or decreased simul- 
taneously, or one can be made to dominate the other through any one or 
more of several different means. 
The recognition of this fact became general when clear-cut quantitative 
results of definite experiments showed that under certain circumstances the 
yields of fruit from the higher plants could be greatly increased when 
nitrogenous fertilizers were applied to them. More critical investigation 
and chemical analyses indicated that those plants which would respond 
in this manner were weakly vegetative and that their nitrogen content 
relative to their dry weight (or, as also shown, to their content of sugars 
and starch-like complexes) was very low. When the nitrogenous fertilizers 
were applied, however, the total relative nitrogen content of the plants 
increased, the plants becoming more strongly vegetative and more fruitful. 
These findings resulted in a third conception concerning the relationship of 
nitrogenous and carbohydrate compoun^is to vegetation and fruiting, 
