THE CHEMICAL CONSTITUTION OF THE UNITS in 



Morner found that cystine, when boiled with alkali, yielded 75 

 per cent of its sulphur as loosely bound sulphur and that, calculating 

 the sulphur content of the keratins from the cystine he had isolated, 

 the amount yielded by these proteins under the same conditions cor- 

 responded very closely ; there were large discrepancies with other pro- 

 teins. He also observed that sulphur was evolved from certain proteins, 

 and other workers have frequently noticed the evolution of sulphur. 

 If no other sulphur-containing compound be present in the proteins, 

 Johnson's suggestion of the presence of thioamide groupings may be 

 the explanation of the anomaly. Thioamides of amino acids are un- 

 known, but Johnson is preparing compounds of this nature. We must 

 hope that his results will fill up this gap in our knowledge. 



