THE IMMEDIATE EFFECT ON MILK PRODUC. 
LION OF CHANGES IN THE RATION,* 
W. P. WHEELER. 
INTRODUCTORY NOTE BY THE DIRECTOR. 
The data discussed in this bulletin were mostly secured under 
a former administration. They are not the result of feeding 
experiments logically planned for the study of rations, but were 
incidental to the extensive breed tests that were carried on fer 
several years, and for this reason they cannot be made the basis 
of so extensive or so safe conclusions as to feeding questions 
~ as otherwise might be the case. 
The tables which Mr. Wheeler presents from nearly one thou- 
sand feeding periods with different animals may seem to be 
duplications in some cases, as for instance V, IX, X of the tables 
as compared with XX VI, XXV and XXVII._ It is to be noticed 
that these tables differ as to the number of periods included, 
which is due to the fact that in one set the selection of data was 
made with reference to the effect of varying the quantity of 
nutrients and in the other set with reference to the influence of 
varying the protein. It is gratifying to note, however, that 
different groups of periods, involving practically similar condi- 
tions, indicate essentially similar conclusions. 
Those who may study this bulletin should keep clearly in 
mind that only the immediate and not the permanent effect of 
rations is considered. Moreover, there should be a proper reser- 
vation of judgment concerning data logically so imperfect. 
Nevertheless, in some particulars these records mean much more 
in a practical way than some offered to the public which involve 
the use of very few animals during only two or three feeding 
*A reprint of Bulletin No, 210, 
