ALBUMINS OR PROTEINS. 267 



no means found in all cases of cystinuria. It is far more probable that the 

 disease is to be regarded as a disturbance in the breaking down of albumin, 

 on the part of the tissues. That the cystine from the albuminous sub- 

 stances in the food is absorbed and assimilated is evident from the fact 

 that the albuminous material in the tissues of a patient afflicted with 

 cystinuria, certainly contains cystine; and that no diminution in the 

 amount of this amino acid can be detected. Cystine is evidently produced 

 in the decomposition of proteins during cell-metabolism, and is not 

 further worked over. It is difficult to say why, in these cases, cystine 

 is not decomposed. A patient afflicted with cystinuria consumes any 

 cystine administered to him, and does not eliminate all the cystine-sulphur 

 as such. It would be easy to imagine some change in the cystine molecule, 

 such that the cell ferments are unable to find any point of attack. We 

 have seen that the cystine from albumin, and that of the urine, are 

 identical. This question must be left unsettled for the present. It may, 

 of course, be possible, that the ferments capable of decomposing cystine 

 are absent from some cells, and that this substance is, therefore, eliminated 

 unchanged. Such an assumption has not, however, been experimentally 

 confirmed. It would start with the hypothesis that each cell possessed 

 a distinct ferment to produce each different amino acid, or group of amino 

 acids. We must say that we have absolutely no proof of such a condition 

 of affairs. We can imagine that cystine might occupy an isolated position 

 on account of its difficult solubility. It is, however, possible that con- 

 ditions may exist in the cells of a person afflicted with cystinuria, which 

 may cause cystine to be thrown out. That cystine may, in time, accu- 

 mulate in the tissues to large proportions, has recently been proved in the 

 case of a boy 21 \ months old. 1 He died with indications of gradual 

 inanition. A post-mortem examination showed all the organs permeated 

 with crystals of cystine. The spleen, for example, was saturated with 

 cystine, and from this organ the pure amino acid could easily be isolated 

 in large quantities. It was interesting that this was a case of inherited 

 cystine diathesis, in fact, in a progressive form. Perhaps some light 

 may be shed upon this rare derangement in metabolism by the obser- 

 vation that other amino acids, besides cystine, may be found in the urine 

 during this disease. 2 Thus, in one case, cystine, leucine, and tyrosine were 

 found. Apparently from this discovery cystinuria corresponds to a more 

 general disturbance in the breaking down of albumins than is usually 

 assumed, and that, to a certain extent, this disease is to be considered as 

 the simplest form of such derangement. We must again state, however, 



1 E. Abderhalden: ibid. 38, 557 (1903). 



2 E. Fischer and U. Suzuki: Z. physiol. Chem. 45, 405 (1905). E. Abderhalden and 

 A. Schittenhelm: ibid. 45, 468 (1905). 



