108 MAINTENANCE RATIONS OF FARM ANIMALS. 



Relative availability of proteins — Thomas — Continued. 





A. 



B. 



C. 



Potatoes 



f 56.37 

 64. 50 

 73. 00 

 80. 33 

 77. 04 

 78. 66 

 1 80. 68 

 \ 77. 62 

 64. 50 

 j 49. 58 

 \ 51.64 

 66.42 

 f 24.55 

 < 12. 25 





68.80 

 72.67 

 78.72 









Cauliflower 



83. 18 



76.22 

 77.45 

 87. 78 

 83.88 

 63.83 

 55.15 

 56.01 

 78.57 

 40.47 

 29. 52 

 3.54 













59. 89 

 59. 89 





Maize I 















In Zisterer's experiments, summarized on page 104, the feed nitrogen is 

 so slightly in excess of the fasting nitrogen katabolism that it would seem that 

 no large error would result from applying Thomas's method of computation. 

 The results are as follows : 



Percentage availability. 





Series I. 



Series II. 



Average. 



Casein 



82. 26 

 90. 60 

 91.97 



83. 77 

 95.40 

 77.45 



83.02 

 93.00 

 84. 71 



Muscle protein 



Wheat gluten 





The results as thus computed are not widely different from those obtained 

 by Thomas for casein and meat protein, but are slightly higher than his results 

 for wheat protein. Michaud's results do not lend themselves to computation in 

 this way. 



Another recent investigation of a different character may be mentioned for 

 the sake of completeness, viz, that on frogs by Busquet, 1 who compared lean 

 veal and mutton with frog meat as regards the amount required to maintain 

 the live weight or to produce a unit of gain of weight in previously fasting 

 frogs. In this respect the veal and mutton were found distinctly inferior to the 

 frog meat per unit of dry matter. 



SIGNIFICANCE OF RESULTS. 



In the comments upon the individual experiments, it has already 

 been clearly indicated that they are open to criticism in many re- 

 spects, such as the noncomparable nature of the protein supply, the 

 lack of due consideration of the supply of mineral matter, etc. 

 Moreover, nearly all the experiments were of relatively short 

 duration. 



Taking the results at their face value, however, they seem to in- 

 dicate distinct differences in the nutritive values of proteins. The 

 entire lack of certain groups, as in the case of gelatin and zein, 



1 Journal de Physiologic et de Pathologie Generale, vol. 11, p. 399. 



