60 Notes from the Physiological Laboratory 



Lately, however, in the course of an admirable 

 paper upon the nutritive relations of gluten, Rubner 1 

 has stated that, although branny foods increase the 

 amount of nitrogen in the faeces, fully three-fourths 

 of the nitrogenous matter of bran is digested. In 

 the bran used there was present 4 per cent, of nitro- 

 gen, "equalling 25 per cent, albuminoids," while 

 in the bran obtained from the faeces of the persons 

 tinder observation only 0.9 per cent, of nitrogen was 

 obtainable. We hesitate in criticising the results of 

 so able an observer, but it seems to us that there 

 were two sources of error in this portion of his 

 investigation. In the digestion of bran the free, 

 adherent gluten, which properly belongs to the more 

 central layers, is, of course, readily dissolved, with a 

 consequent reduction in the nitrogen of the bran. 

 Apart from this, however, a loss in nitrogen is to be 

 expected, from the diffusion of nitrogenous crystal- 

 loids. Further, the "gluten-cells" become so sepa- 

 rated from the true bran, during their maceration in 

 the intestinal contents, that it is nearly, if not quite, 

 impossible to recover them. 



In order to satisfy ourselves regarding the diges- 

 tibility of the cells of the fourth coat, we have 



1 Zeitscb. f. Biologie, vol. xix. 1883, p. 46. 



