117 
easily performed, and when this work is presented to the public, as I hope it soon 
will be, the methods will be fully described, and it will he a simple problem for any 
one of yon to use this method in developing new and important fields of research as 
to the chemistry of the soil and its relation to crop production. The work is not 
going to be finished with the publication of this new bulletin; it will have only begun. 
It is going to open new fields and new ideas and new possibilities of studying this 
fundamental question of the relation of soils to crop production. 
If there are any questions that I have not made clear, or that any of you want to be 
informed upon, I shall he very glad to have the questions asked. 
L. II. Bailey, of New York, asked some questions regarding the specific physi- 
ological effect of fertilizers, which Professor Whitney said had not yet been definitely 
determined. 
Chemistry of Soils as Related to Croc Production — Bureau ok Soils Bulletin 
No. 22. a 
The following paper, by E. W. Hilgard, of California, on this subject, was read by 
C. E. Thorne: 
The following quotations will best define the scope of this bulletin of seventy-one 
pages and the theses which it is intended to establish and maintain: 
Page 7. "The investigations made by the Bureau of Soils during the last ten years 
have shown that the economic distribution of crops is dependent mainly upon the 
physical characters of soils and upon climate." 
Page 13. "Briefly stated, the results given in the following pages appear to show, 
contrary to opinions which have long been held, that there is no obvious relation 
between the chemical composition of a soil as determined by the methods of analysis 
used and the yield of crops, but that the chief factor determining the yield is the 
physical condition of the soil under suitable climatic conditions." 
Page 63. "The exhaustive investigation of many types of soil by very accurate 
methods of analysis under many conditions of cultivation and cropping, in areas 
yielding large crops and in adjoining areas yielding small crops, has shown that there 
is no obvious relation between the amount of the several nutritive ingredients in the 
soil and in the yield of crops." 
Page 64. "It appears further that practically all soils contain sufficient plant food 
for good crop yield; that this supply will be indefinitely maintained, and that the 
actual yield of plants adapted to the soils depends mainly, under favorable climatic 
conditions, upon the cultural methods, a conclusion strictly in accord with the expe- 
rience of good farm practice in all countries." 
The bulletin contains extended tables showing the results of the analytical work, 
and at the end a full description of the methods employed therein. 
The above four paragraphs, taken respectively from the beginning and the latter 
part of the bulletin, summarize the conclusions to which, as it states, "the Bureau 
of Soils has been forced." 
These conclusions are certainly startling, to say the least, and perhaps not the 
least remarkable is the concluding one, which hardly agrees with the impressions 
left upon the mind of most of those who have made themselves acquainted with the 
history of agriculture and its past and present practice in the most advanced civili- 
zations. 
Were such statements to emanate from a private laboratory on a mere personal 
responsibility it would be likely to be passed over and allowed to run its course; 
but when it emanates from the head of the Bureau of Soils in the U. S. Department 
of Agriculture, and is expressly and persistently given as the opinion of that Bureau, 
it can not be thus passed over unchallenged. 
The above quotation from page 7 of the bulletin practically prejudges or begs the 
main question at issue. To anyone outside of the Bureau the cogency of this state- 
ment is far from apparent, except in so far as it may mean what has long been known 
and recognized and need not therefore have been shown anew by the Bureau. 
If we examine the experimental basis upon which all these assertions are made, 
we find it to be the assumption that the aqueous soil solution is the exclusive source 
through which plants derive their food, and the fact assumed to be demonstrated by 
a newly devised method of analysis that that solution is practically of the same 
composition in all soils, so far as the mainly important plant food ingredients are 
concerned. Throughout the bulletin the determinations thus made are considered 
« See also Science, 18 (1903), No. 467, p. 755. 
