Amides of Meconic and Comenic Acids. 213 



to such weight as to compel me to return to the subject, and 

 endeavour either to discover the source of error, or to show 

 sufficient reasons for the validity of my own assumption. 

 The substance alluded to was produced by the action of am- 

 monia on the monoethylated meconic acid ; a yellow salt 

 being thus formed having a most peculiar non-crystalline 

 structure, as it occurs in the state of transparent rounded 

 grains, which completely resemble drops of oil. This is an 

 ammonia salt, from which an excess of hydrochloric acid 

 throws down the acid in question as a white crystalline pow- 

 der or crust. 



I now recapitulate the analyses of this substance, as for- 

 merly published, and add some remarks from my note-book, 

 made at the time of the analyses, but not given with them in 

 the paper. I do this in order to meet the objections taken to 

 the conclusions drawn from these experiments, on the ground 

 that the substance possibly contained ammonia, and, not 

 being crystallizable, might not easily be obtained pure. The 

 analytical numbers I place in juxtaposition with my own for- 

 mula, and that proposed by Wurtz and Gerhardt, which is 

 indeed that of the substance I was in search of, and which, 

 after a similar comparison in the paper before mentioned, I 

 was compelled to reject as discordant with experimental evi- 

 dence. The figures are : — 



I. II. III. IV. 



7-70 



Carbon, 



39-73 



39-65 



39-50 



Hydrogen, 



3-30 



3-32 



3-26 



Oxygen, 



49-13 



48-98 





Nitrogen, 



784 



8-05 





100-00 100-00 100-00 100-00 



and I find, by referring to my notes, that I. and n. were from 

 materials of different preparations, in each case consisting of 

 solution of the yellow granular salt in hot water, addition of 

 strong hydrochloric acid in excess and the subsequent re- 

 crystallization from boiling water of the substance so pre- 

 cipitated. The remark noted after these results is, " ammonia 

 seems to adhere to this substance," and the residue of that 

 employed for analysis II. was dissolved in boiling water, some 



