OP ARTS AND SCIENCES. 123 



which shows that dissociation takes place on warming. On add- 

 ing phenylhydrazine to a lukewarm solution of the hydrate in ben- 

 zine, the hydrazon-hydrate already mentioned above separates out 

 in white rlakes. Mesoxanilidehydrate, heated in a capillary tube, 

 behaves just like the corresponding alcoholate (see p. 119); heated 

 at 100°, it loses one molecule of water very slowly, going over into 

 yellow mcsoxanilide. It requires about fifteen hours' heating at 

 100°-110°. 



The most remarkable property of this substance is, however, its 

 acid nature; it reddens blue litmus in aqueous solution, and dis- 

 solves without change in dilute sodic hydrate and carbonate. 



The fact that a substance containing the carbonyl group can 

 attain acid properties by taking up one molecule of water, 



pOH 

 /OH 



as well as the proof that phenylhydrazine simply adds itself in the 

 first stage to a carbonyl group, 



C 6 H 6 NHNH 



c 6 h 5 nhnh 2 + oc; = ;cr 



x HO x x 



I regard as the most important result of the work on mesoxani- 

 lide. They will be fully discussed in connection with other ob- 

 servations at the end of this paper. I would like, however, to 

 make here a few remarks concerning the constitution of the acid 

 amides. It seems to me that the interesting experiments of Tafel 

 and Enoch, in the case of benzamide,* and of Comstock and Klee- 

 berg,f in the case of formanilide, have made it very probable that 

 the acid amides possess the constitution represented by the formula 



.OH 

 EC' 



^NH 



It follows that the product obtained by the action of ammonia on 



an acid ether, 



.0 



E-C^ 



N OE 



* Ber. d. chem. Ges., XXIII. 103 and 1550. 

 t American Chem. Journal, XII. 493. 



