16 



boiling many organic substances with alkaline permanganate until dis- 

 tillation has practically brought the contents of the retort to dryuess, 

 without all of the nitrogen present having been given off. And some 

 other causes of trouble were noticed; as, for instance, the loss of oxygen 

 given off as such from a strong and acid solution of permanganate on 

 standing in a heated condition irrespective of action on the organic 

 matter present. 



The general tenor of the results in the case of the nitrogenous sub- 

 stances treated pointed to more energetic and extensive action of per- 

 manganate in alkaline than in acid solution ; also to more extensive 

 action on the simpler amidic compounds than on the proteids. But 

 notwithstanding sundry variations of method as to strength of the 

 reagent solutions, proportion of reagent to organic material acted on, 

 temperature and time of action, no indication was obtained of any 

 valid basis for distinction in analysis between the two classes of 

 nitrogenous material studied. 



INTERACTION WITH SODIUM HYPOBROM1TE. 



This reaction is so frequently used for the approximate determina- 

 tion of urea (carbamid), while its results with other amids have been 

 so scantily examined and almost no facts bearing on its relation to the 

 proteids have been recorded that a good deal of interest was felt in 

 examining it somewhat extensively with the two classes of materials 

 which were studied. 



The solution of bromin was prepared with 240 grams of potassium 

 broinid, 200 grams of free bromin, and enough water to make up a 

 liter. The solution of caustic soda was made with 340 grams of pure 

 sodium hydroxid to the liter. These solutions were preserved in sep- 

 arate bottles and equal volumes of the two were mixed just before 

 using. When undiluted the mixture represented 0.1 gram of originally 

 free bromin to each cubic centimeter and was in most of the experi- 

 ments used of this strength; but various dilutions were also employed, 

 being made by additions of water in definite amount. 



The apparatus with which the reaction was carried out was essen- 

 tially the same as that adopted for the experiments with nitrous acid, 

 save that the small tube was omitted which was intended to introduce 

 an inert gas to displace air from the apparatus, this prec aution being 

 unnecessary in the hypobromite experiments. 



Nearly 80 experiments were made, varying the conditions as to tem- 

 perature from that of the atmosphere, usually 15 to 20, up to 06 to 

 98 O., as to pressure within the limits allowed by the immersion of the 

 gas-measuring cylinder, and as to time from fifteen or twenty minutes 

 up to five or six hours. 



In some cases the results obtained were in agreement with those of 

 the few hitherto recorded experiments as, for instance, aspartic acid 

 gave no nitrogen, as was found to be the fact by Allen and Tankard. 



