Robert A. Steinberg 3 6 3 



these compounds in these phenomena (48, 49). These data are included 

 at the end of this paper. 



Certain assumptions and simplifications have been introduced in the 

 data of the literature here reproduced. All values have been recomputed 

 in terms of "deficiency/control," i.e., content of a constituent in the 

 deficient plants divided by that in the controls. Variations as between 

 chemical methods so tend to be minimized. Carbon values are limited 

 to total carbohydrate exclusive of hemicellulose and cellulose, and its 

 major cleavage product— reducing sugar. Nitrogen values are similarly 

 limited to protein and the major cleavage product— amino acid. Values 

 for soluble nitrogen have also been used, particularly if corrected for 

 nitrate. 



Four points have been kept in mind by the writer in the evaluation 

 of the numerical data, (a) The selected data and the conclusions they 

 entail concerning the individual researches are those of the investigators 

 whose papers are cited, (b) The data in these publications have been 

 recomputed for use in these tables and should be compared on a relative 

 and individual basis. That is they should be compared in pairs: free 

 amino nitrogen versus protein, and reducing sugar versus carbohydrate. 

 While many of the tabulated values are also true on an absolute basis, 

 this is considered relatively immaterial from the viewpoint of consecu- 

 tive chemical reactions, (c) Mild or no symptoms are given equal 

 weights in the means and the total number of positive results despite 

 any proof other than the intention of the investigator that a deficiency 

 existed, (d) The calculated means and the number of positive results 

 are used as a rough measure of the extent of agreement in investiga- 

 tions. However, the degree of mineral deficiency, the magnitude of 

 differences in pairs of values, and the extent and consistency of the 

 values in each investigation are also used as aids in interpretation. 



EFFECTS OF MINERAL DEFICIENCIES ON THE 

 PROTEIN AND AMINO ACID CONTENT OF PLANTS 



A summary of the results reported by investigators as concerns the 

 effects of mineral deficiency on protein metabolism is contained in 

 Tables I— III. These results are limited on the whole to leaves and stem. 

 Special procedures of sampling such as the use of fractional parts of the 



