88 THE PHYSIOLOGY OF PROTEIN METABOLISM 



tion of the sulphur output for estimating the protein breakdown is a 

 technical one the method of estimation is comparatively slow. Von 

 Wendt held that it was only by the combined examination of the 

 nitrogen and sulphur output that a true picture of the total protein 

 exchange in the body could be obtained ; individually they only indi- 

 cated the excretion of certain decomposition products. He found that 

 the tissues first burned and excreted the sulphur-rich digestion pro- 

 ducts of the protein, and that the nitrogenous compounds, which were 

 retained in the body, were poor in sulphur. The maximal output of 

 sulphur preceded the maximal output of nitrogen. It was suggested 

 that this retained material might be some decomposition product which, 

 although it was not a true protein, could not be washed out of the 

 tissues. Rubner also found that the sulphur output preceded the 

 nitrogen output 



Gruber, on the other hand, found that the output of nitrogen and 

 sulphur ran parallel, and concluded that the protein material stored for 

 use in the tissues resembled normal protein. Sherman and Hawk 

 (371 A) and Siven (374) also found that the output of nitrogen and 

 sulphur ran very nearly parallel. Ehrstrom (m) found that the 

 nitrogen and sulphur output ran nearly parallel, but that on the whole 

 the sulphur adapted itself more rapidly to changes in the intake. He 

 suggested that the protein products most deeply split were richest in 

 sulphur, and possibly that they underwent oxidation in the tissues 

 first, thus accounting for the more rapid excretion of sulphur some- 

 times observed. His work, therefore, lends support to that of Von 

 Wendt. 



Hamalainen and Helme (167) have also investigated the rate of 

 the nitrogen and sulphur output, using the superposition method in- 

 troduced by Falta, in which the material to be tested is added to a 

 standard diet, or ground ration. Their standard diet was one poor in 

 nitrogen, and on this they superimposed at different times egg white, 

 proton, and roast veal. Of the three diets apparently the veal alone 

 was able to supply the deficiency in nitrogen and thus replace the wasted 

 tissue protein. This was only to be expected, in accordance with the 

 later work of Michaud (284), as veal protein more closely resembles 

 tissue protein than either of the other two substances. They held that 

 their results supported the hypothesis of Von Wendt that the sulphur- 

 rich products of protein digestion were more rapidly burnt and excreted 

 than those which contained less sulphur. 



The following table details their most important results : 



