— 195 — 



In conclusion, Erlenmeyer and Hilgendorff *), and Erlenmeyer 2 ), in con- 

 IP nection with the investigations mentioned above, engage in theoretical 

 considerations of the problem whether molecular asymmetric storacic 

 cinnamic acids can exist, and of isomerism in ethylene derivarives. We 

 regret that considerations of space compel us to restrict ourselves to a 

 bare mention of these interesting questions. 



The chlorine-free benzaldehyde, and part of the natural bitter almond 

 oil used in these investigations had been placed at the authors' disposal by us. 



Some further reference must also be made to the researches of 

 H. Stobbe and F. Reuss 3 ), and of Stobbe 4 ). Stobbe and Reuss investigated 

 the optical refraction of the melted acids and discovered that in a range 

 of temperature of about 50° the meltings of alio- and ^socinnamic acids 

 have the same refraction and that therefore they must be regarded as 

 optically identical. Stobbe (loc. cit.) has further occupied himself with 

 the conversions of the alio- and isocinnamic acids in the flux and in the 

 crystalline form. His conclusion is that there exist two different isomeric 

 cinnamic acids, viz., monomorphous allocinnamic acid (m. p. 68°) and di- 

 morphous isocinnamic acid (m. p. 58° and 42°). This so-called-conclusion 

 appears to him to afford the best summary of the alio- and ^ocinnamic 

 acid question, taking also into account the results obtained by all other 

 investigators. 



According to Meyer 5 ), the researches of Stobbe do not supply suf- 

 ficient experimental material to warrant the adoption of the theory of chem- 

 ical isomerism between the a^ocinnamic acid with m. p. 68° on the one 

 hand and the acids melting at 58 and 42° on the other. 



Finally, H. R. Kruyt 6 ) controverts not only Stobbe but also Meyer's 

 criticism of the latter. 



Nitrogenous bodies. 



According to N. Kishner 7 ) hydrazine compounds are capable of being 

 resolved into hydrocarbons and nitrogen by boiling them with solid po- 

 tassium hydroxide. Thus, 1 , 3-methylci/cfohexylidene hydrazine yields methyl- 

 q/dohexane; camphylidene hydrazine (m. p. 53 to 55°) yields camphane 

 (m. p. 158 to 159°); fenchylidene hydrazine yields fenchane (b. p. 151,5°) 

 and q/cZohexylidene hydrazine hydrate yields q/cfohexane. The dihydro- 



* x ) Biochem. Zeitschr. 35 (1912), 134. 



* 2 ) Ibidem 149. 



3 ) Berl. Berichte 44 (1911), 2735. 

 *) Ibidem 2739. 

 5 ) Ibidem 2966. 

 «) Ibidem 3108. 



7 ) Journ. russ. phys. chem. Ges. 43 (1911), 582, 951. Quoted from Chem. Zentralbl. 1911, 

 II. 363, 1925. 



13* 



